diff --git a/optuna/importance/__init__.py b/optuna/importance/__init__.py
index 634e8bdbc0..3849ee9dc0 100644
--- a/optuna/importance/__init__.py
+++ b/optuna/importance/__init__.py
@@ -2,10 +2,8 @@
 from typing import Dict
 from typing import List
 from typing import Optional
-import warnings
 
 from optuna._experimental import warn_experimental_option
-from optuna.exceptions import ExperimentalWarning
 from optuna.importance._base import BaseImportanceEvaluator
 from optuna.importance._fanova import FanovaImportanceEvaluator
 from optuna.importance._mean_decrease_impurity import MeanDecreaseImpurityImportanceEvaluator
diff --git a/optuna/samplers/_cmaes.py b/optuna/samplers/_cmaes.py
index 6c9dce9d71..bdc064c1ea 100644
--- a/optuna/samplers/_cmaes.py
+++ b/optuna/samplers/_cmaes.py
@@ -14,7 +14,6 @@
 from typing import Tuple
 from typing import TYPE_CHECKING
 from typing import Union
-import warnings
 
 import numpy as np
 
@@ -26,7 +25,6 @@
 from optuna.distributions import BaseDistribution
 from optuna.distributions import FloatDistribution
 from optuna.distributions import IntDistribution
-from optuna.exceptions import ExperimentalWarning
 from optuna.samplers import BaseSampler
 from optuna.samplers._lazy_random_state import LazyRandomState
 from optuna.search_space import IntersectionSearchSpace
diff --git a/optuna/samplers/_tpe/sampler.py b/optuna/samplers/_tpe/sampler.py
index 153a1ae79c..7666657c81 100644
--- a/optuna/samplers/_tpe/sampler.py
+++ b/optuna/samplers/_tpe/sampler.py
@@ -17,7 +17,6 @@
 from optuna._hypervolume.hssp import _solve_hssp
 from optuna.distributions import BaseDistribution
 from optuna.distributions import CategoricalChoiceType
-from optuna.exceptions import ExperimentalWarning
 from optuna.logging import get_logger
 from optuna.samplers._base import _CONSTRAINTS_KEY
 from optuna.samplers._base import _process_constraints_after_trial
diff --git a/optuna/samplers/nsgaii/_sampler.py b/optuna/samplers/nsgaii/_sampler.py
index 0a89c61bb9..7c603b5593 100644
--- a/optuna/samplers/nsgaii/_sampler.py
+++ b/optuna/samplers/nsgaii/_sampler.py
@@ -6,12 +6,10 @@
 import hashlib
 from typing import Any
 from typing import TYPE_CHECKING
-import warnings
 
 import optuna
 from optuna._experimental import warn_experimental_option
 from optuna.distributions import BaseDistribution
-from optuna.exceptions import ExperimentalWarning
 from optuna.samplers._base import BaseSampler
 from optuna.samplers._lazy_random_state import LazyRandomState
 from optuna.samplers._random import RandomSampler
diff --git a/optuna/visualization/_pareto_front.py b/optuna/visualization/_pareto_front.py
index 755ca4ba3f..0b31be2488 100644
--- a/optuna/visualization/_pareto_front.py
+++ b/optuna/visualization/_pareto_front.py
@@ -8,7 +8,6 @@
 
 import optuna
 from optuna._experimental import warn_experimental_option
-from optuna.exceptions import ExperimentalWarning
 from optuna.study import Study
 from optuna.study._multi_objective import _get_pareto_front_trials_by_trials
 from optuna.trial import FrozenTrial