diff --git a/sklearn/tree/_tree.pxd b/sklearn/tree/_tree.pxd
index b99f44c0472a2..59e9957d3d1b8 100644
--- a/sklearn/tree/_tree.pxd
+++ b/sklearn/tree/_tree.pxd
@@ -28,7 +28,7 @@ cdef struct Node:
     SIZE_t left_child                    # id of the left child of the node
     SIZE_t right_child                   # id of the right child of the node
     SIZE_t feature                       # Feature used for splitting the node
-    DOUBLE_t threshold                   # Threshold value at the node
+    SIZE_t threshold                   # Threshold value at the node
     DOUBLE_t impurity                    # Impurity of the node (i.e., the value of the criterion)
     SIZE_t n_node_samples                # Number of samples at the node
     DOUBLE_t weighted_n_node_samples     # Weighted number of samples at the node