diff --git a/optuna_dashboard/ts/components/GraphContour.tsx b/optuna_dashboard/ts/components/GraphContour.tsx
index 5005883a..76191ce8 100644
--- a/optuna_dashboard/ts/components/GraphContour.tsx
+++ b/optuna_dashboard/ts/components/GraphContour.tsx
@@ -12,14 +12,17 @@ import {
   useTheme,
 } from "@mui/material"
 import blue from "@mui/material/colors/blue"
-import { GraphContainer, useGraphComponentState } from "@optuna/react"
+import {
+  GraphContainer,
+  useGraphComponentState,
+  useMergedUnionSearchSpace,
+} from "@optuna/react"
 import * as plotly from "plotly.js-dist-min"
 import React, { FC, useEffect, useMemo, useState } from "react"
 import { SearchSpaceItem, StudyDetail, Trial } from "ts/types/optuna"
 import { PlotType } from "../apiClient"
 import { getAxisInfo } from "../graphUtil"
 import { usePlot } from "../hooks/usePlot"
-import { useMergedUnionSearchSpace } from "../searchSpace"
 import { usePlotlyColorTheme } from "../state"
 import { useBackendRender } from "../state"
 
diff --git a/optuna_dashboard/ts/components/GraphParallelCoordinate.tsx b/optuna_dashboard/ts/components/GraphParallelCoordinate.tsx
index 22cf3aa9..0f26025d 100644
--- a/optuna_dashboard/ts/components/GraphParallelCoordinate.tsx
+++ b/optuna_dashboard/ts/components/GraphParallelCoordinate.tsx
@@ -6,7 +6,11 @@ import {
   Typography,
   useTheme,
 } from "@mui/material"
-import { GraphContainer, useGraphComponentState } from "@optuna/react"
+import {
+  GraphContainer,
+  useGraphComponentState,
+  useMergedUnionSearchSpace,
+} from "@optuna/react"
 import {
   Target,
   useFilteredTrials,
@@ -19,7 +23,6 @@ import React, { FC, ReactNode, useEffect, useState } from "react"
 import { SearchSpaceItem, StudyDetail } from "ts/types/optuna"
 import { PlotType } from "../apiClient"
 import { usePlot } from "../hooks/usePlot"
-import { useMergedUnionSearchSpace } from "../searchSpace"
 import { usePlotlyColorTheme } from "../state"
 import { useBackendRender } from "../state"
 
diff --git a/optuna_dashboard/ts/components/GraphRank.tsx b/optuna_dashboard/ts/components/GraphRank.tsx
index 5d7e2bdd..bf3c0711 100644
--- a/optuna_dashboard/ts/components/GraphRank.tsx
+++ b/optuna_dashboard/ts/components/GraphRank.tsx
@@ -8,14 +8,17 @@ import {
   Typography,
   useTheme,
 } from "@mui/material"
-import { GraphContainer, useGraphComponentState } from "@optuna/react"
+import {
+  GraphContainer,
+  useGraphComponentState,
+  useMergedUnionSearchSpace,
+} from "@optuna/react"
 import * as plotly from "plotly.js-dist-min"
 import React, { FC, useEffect, useState } from "react"
 import { SearchSpaceItem, StudyDetail, Trial } from "ts/types/optuna"
 import { PlotType } from "../apiClient"
 import { getAxisInfo, makeHovertext } from "../graphUtil"
 import { usePlot } from "../hooks/usePlot"
-import { useMergedUnionSearchSpace } from "../searchSpace"
 import { useBackendRender, usePlotlyColorTheme } from "../state"
 
 const plotDomId = "graph-rank"
diff --git a/optuna_dashboard/ts/components/GraphSlice.tsx b/optuna_dashboard/ts/components/GraphSlice.tsx
index 126b7ff4..d404c2cf 100644
--- a/optuna_dashboard/ts/components/GraphSlice.tsx
+++ b/optuna_dashboard/ts/components/GraphSlice.tsx
@@ -9,7 +9,11 @@ import {
   Typography,
   useTheme,
 } from "@mui/material"
-import { GraphContainer, useGraphComponentState } from "@optuna/react"
+import {
+  GraphContainer,
+  useGraphComponentState,
+  useMergedUnionSearchSpace,
+} from "@optuna/react"
 import {
   Target,
   useFilteredTrials,
@@ -22,7 +26,6 @@ import React, { FC, useEffect, useState } from "react"
 import { SearchSpaceItem, StudyDetail } from "ts/types/optuna"
 import { PlotType } from "../apiClient"
 import { usePlot } from "../hooks/usePlot"
-import { useMergedUnionSearchSpace } from "../searchSpace"
 import { useBackendRender, usePlotlyColorTheme } from "../state"
 
 const plotDomId = "graph-slice"
diff --git a/tslib/react/src/index.ts b/tslib/react/src/index.ts
index 6f236a2e..e1b4243f 100644
--- a/tslib/react/src/index.ts
+++ b/tslib/react/src/index.ts
@@ -17,4 +17,5 @@ export {
   useObjectiveAndUserAttrTargets,
   useObjectiveAndUserAttrTargetsFromStudies,
 } from "./utils/trialFilter"
+export { useMergedUnionSearchSpace } from "./utils/searchSpace"
 export type { GraphComponentState } from "./types"