diff --git a/src/multi_objective.rs b/src/multi_objective.rs
index a82b1ad..9b924f3 100644
--- a/src/multi_objective.rs
+++ b/src/multi_objective.rs
@@ -55,7 +55,7 @@ use crate::distribution::Distribution;
 use crate::param::ParamValue;
 use crate::parameter::{ParamId, Parameter};
 use crate::pruner::NopPruner;
-use crate::sampler::random::RandomSampler;
+use crate::sampler::random::RandomMultiObjectiveSampler;
 use crate::sampler::{CompletedTrial, Sampler};
 use crate::trial::{AttrValue, Trial};
 use crate::types::{Direction, TrialState};
@@ -154,31 +154,6 @@ pub trait MultiObjectiveSampler: Send + Sync {
     ) -> ParamValue;
 }
 
-// ---------------------------------------------------------------------------
-// RandomMultiObjectiveSampler
-// ---------------------------------------------------------------------------
-
-/// Default MO sampler that delegates to [`RandomSampler`].
-pub(crate) struct RandomMultiObjectiveSampler(RandomSampler);
-
-impl RandomMultiObjectiveSampler {
-    pub(crate) fn new() -> Self {
-        Self(RandomSampler::new())
-    }
-}
-
-impl MultiObjectiveSampler for RandomMultiObjectiveSampler {
-    fn sample(
-        &self,
-        distribution: &Distribution,
-        trial_id: u64,
-        _history: &[MultiObjectiveTrial],
-        _directions: &[Direction],
-    ) -> ParamValue {
-        self.0.sample(distribution, trial_id, &[])
-    }
-}
-
 // ---------------------------------------------------------------------------
 // MoSamplerBridge — bridges MultiObjectiveSampler to Sampler trait
 // ---------------------------------------------------------------------------
diff --git a/src/sampler/random.rs b/src/sampler/random.rs
index 292fe4a..7dc31ef 100644
--- a/src/sampler/random.rs
+++ b/src/sampler/random.rs
@@ -30,9 +30,11 @@
 use parking_lot::Mutex;
 
 use crate::distribution::Distribution;
+use crate::multi_objective::{MultiObjectiveSampler, MultiObjectiveTrial};
 use crate::param::ParamValue;
 use crate::rng_util;
 use crate::sampler::{CompletedTrial, Sampler};
+use crate::types::Direction;
 
 /// Uniform independent random sampler.
 ///
@@ -79,6 +81,27 @@ impl RandomSampler {
     }
 }
 
+/// Default multi-objective sampler that delegates to [`RandomSampler`].
+pub(crate) struct RandomMultiObjectiveSampler(RandomSampler);
+
+impl RandomMultiObjectiveSampler {
+    pub(crate) fn new() -> Self {
+        Self(RandomSampler::new())
+    }
+}
+
+impl MultiObjectiveSampler for RandomMultiObjectiveSampler {
+    fn sample(
+        &self,
+        distribution: &Distribution,
+        trial_id: u64,
+        _history: &[MultiObjectiveTrial],
+        _directions: &[Direction],
+    ) -> ParamValue {
+        self.0.sample(distribution, trial_id, &[])
+    }
+}
+
 impl Default for RandomSampler {
     fn default() -> Self {
         Self::new()