diff --git a/src/main/java/com/mapconductor/template/TemplateMapViewController.kt b/src/main/java/com/mapconductor/template/TemplateMapViewController.kt
index 80d5d04..d0bd849 100644
--- a/src/main/java/com/mapconductor/template/TemplateMapViewController.kt
+++ b/src/main/java/com/mapconductor/template/TemplateMapViewController.kt
@@ -147,6 +147,8 @@ class TemplateMapViewController(
         circleController.clear()
         groundImageController.clear()
         rasterLayerController.clear()
+        // 拡張モジュール（クラスタリングなど）が登録した Strategy のマーカーも消す。
+        clearStrategyMarkerControllers()
     }
 
     /**
diff --git a/src/test/java/com/mapconductor/template/TemplateClearOverlaysStrategyTest.kt b/src/test/java/com/mapconductor/template/TemplateClearOverlaysStrategyTest.kt
new file mode 100644
index 0000000..df9f19b
--- /dev/null
+++ b/src/test/java/com/mapconductor/template/TemplateClearOverlaysStrategyTest.kt
@@ -0,0 +1,121 @@
+package com.mapconductor.template
+
+import androidx.compose.ui.geometry.Size
+import com.mapconductor.core.features.GeoPoint
+import com.mapconductor.core.features.GeoRectBounds
+import com.mapconductor.core.map.MapCameraPosition
+import com.mapconductor.core.map.MapViewHolderInterface
+import com.mapconductor.core.map.VisibleRegion
+import com.mapconductor.core.marker.MarkerEntity
+import com.mapconductor.core.marker.MarkerEntityInterface
+import com.mapconductor.core.marker.MarkerManager
+import com.mapconductor.core.marker.MarkerOverlayRendererInterface
+import com.mapconductor.core.marker.MarkerRenderingStrategyInterface
+import com.mapconductor.core.marker.MarkerState
+import com.mapconductor.core.marker.OnMarkerEventHandler
+import com.mapconductor.core.marker.StrategyMarkerController
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.runBlocking
+import org.junit.Assert.assertEquals
+import org.junit.Test
+
+/**
+ * `clearOverlays()` は、クラスタリングなどの拡張モジュールが registerOverlayController で
+ * 登録した StrategyMarkerController も消す。ドライバーを書くときは
+ * `clearStrategyMarkerControllers()` を clearOverlays() から呼ぶこと。
+ */
+class TemplateClearOverlaysStrategyTest {
+    private val scope = CoroutineScope(Dispatchers.Unconfined)
+
+    private fun newDriver(): TemplateMapViewController {
+        val map = TemplateMap()
+        map.viewportSize = Size(1000f, 1000f)
+        val holder = TemplateMapViewHolder(TemplateMapSurface(map), map)
+        return TemplateMapViewController(
+            holder = holder,
+            markerController = TemplateMarkerController(TemplateMarkerRenderer(holder, scope)),
+            polylineController = TemplatePolylineController(TemplatePolylineRenderer(holder)),
+            polygonController = TemplatePolygonController(TemplatePolygonRenderer(holder)),
+            circleController = TemplateCircleController(TemplateCircleRenderer(holder)),
+            groundImageController = TemplateGroundImageController(TemplateGroundImageRenderer(holder)),
+            rasterLayerController = TemplateRasterLayerController(TemplateRasterLayerRenderer(holder, scope)),
+            mainCoroutine = scope,
+            defaultCoroutine = scope,
+        )
+    }
+
+    private class GlRenderer(
+        private val manager: MarkerManager<String>,
+    ) : MarkerOverlayRendererInterface<String> {
+        var drawn: List<String> = emptyList()
+        override var animateStartListener: OnMarkerEventHandler? = null
+        override var animateEndListener: OnMarkerEventHandler? = null
+        override val holder: MapViewHolderInterface<*, *>
+            get() = throw UnsupportedOperationException("not used")
+
+        override suspend fun onAdd(data: List<MarkerOverlayRendererInterface.AddParamsInterface>) = data.map { it.state.id }
+
+        override suspend fun onChange(data: List<MarkerOverlayRendererInterface.ChangeParamsInterface<String>>) =
+            data.map { it.current.state.id }
+
+        override suspend fun onRemove(data: List<MarkerEntityInterface<String>>) = Unit
+
+        override suspend fun onAnimate(entity: MarkerEntityInterface<String>) = Unit
+
+        override suspend fun onPostProcess() {
+            drawn = manager.allEntities().map { it.state.id }
+        }
+    }
+
+    private class DrawAllStrategy : MarkerRenderingStrategyInterface<String> {
+        override val markerManager: MarkerManager<String> = MarkerManager.defaultManager()
+
+        override fun clear() = markerManager.clear()
+
+        override suspend fun onUpdate(
+            state: MarkerState,
+            viewport: GeoRectBounds,
+            renderer: MarkerOverlayRendererInterface<String>,
+        ) = true
+
+        override suspend fun onAdd(
+            data: List<MarkerState>,
+            viewport: GeoRectBounds,
+            renderer: MarkerOverlayRendererInterface<String>,
+        ): Boolean {
+            data.forEach { markerManager.registerEntity(MarkerEntity(marker = it.id, state = it, isRendered = true)) }
+            renderer.onPostProcess()
+            return true
+        }
+
+        override suspend fun onCameraChanged(
+            cameraPosition: MapCameraPosition,
+            renderer: MarkerOverlayRendererInterface<String>,
+        ) = Unit
+    }
+
+    @Test
+    fun `clearOverlays は登録された Strategy のマーカーも消す`() =
+        runBlocking {
+            val driver = newDriver()
+            val strategy = DrawAllStrategy()
+            val renderer = GlRenderer(strategy.markerManager)
+            val controller = StrategyMarkerController(strategy, renderer)
+            driver.registerOverlayController(controller)
+            val bounds = GeoRectBounds(GeoPoint(34.0, 138.0), GeoPoint(36.0, 140.0))
+            controller.onCameraChanged(
+                MapCameraPosition(
+                    position = GeoPoint(35.0, 139.0),
+                    zoom = 10.0,
+                    visibleRegion = VisibleRegion(bounds, null, null, null, null),
+                ),
+            )
+            controller.add(listOf(MarkerState(position = GeoPoint(35.0, 139.0), id = "s1")))
+            assertEquals(listOf("s1"), renderer.drawn)
+
+            driver.clearOverlays()
+
+            assertEquals(emptyList<String>(), renderer.drawn)
+        }
+}