diff --git a/package/samplers/hebo/requirements.txt b/package/samplers/hebo/requirements.txt
index a9121a3e..67584885 100644
--- a/package/samplers/hebo/requirements.txt
+++ b/package/samplers/hebo/requirements.txt
@@ -1,3 +1,5 @@
+numpy
 optuna
 optunahub
+pandas
 hebo@git+https://github.com/huawei-noah/HEBO.git#subdirectory=HEBO
diff --git a/package/samplers/hebo/sampler.py b/package/samplers/hebo/sampler.py
index 35bfcdde..e206beaa 100644
--- a/package/samplers/hebo/sampler.py
+++ b/package/samplers/hebo/sampler.py
@@ -1,13 +1,19 @@
 from __future__ import annotations
 
+from typing import Optional
+from typing import Sequence
+
 from optuna.distributions import BaseDistribution
 from optuna.distributions import CategoricalDistribution
 from optuna.distributions import FloatDistribution
 from optuna.distributions import IntDistribution
 from optuna.study import Study
-from optuna.trial import FrozenTrial
+from optuna.trial import FrozenTrial, TrialState
 import optunahub
 
+import numpy as np
+import pandas as pd
+
 from hebo.design_space.design_space import DesignSpace
 from hebo.optimizers.hebo import HEBO
 
@@ -30,6 +36,15 @@ def sample_relative(
             params[name] = params_pd[name].to_numpy()[0]
         return params
 
+    def after_trial(
+        self,
+        study: Study,
+        trial: FrozenTrial,
+        state: TrialState,
+        values: Optional[Sequence[float]],
+    ) -> None:
+        self._hebo.observe(pd.DataFrame([trial.params]), np.asarray([values]))
+
     def _convert_to_hebo_design_space(
         self, search_space: dict[str, BaseDistribution]
     ) -> DesignSpace: