A SiC semiconductor device includes: a SiC substrate having a main surface; a channel region on the substrate; first and second impurity regions on upstream and downstream sides of the channel region, respectively; a gate on the channel region through a gate insulating film. The channel region for flowing current between the first and second impurity regions is controlled by a voltage applied to the gate. An interface between the channel region and the gate insulating film has a hydrogen concentration equal to or greater than 2.6×1020 cm−3. The interface provides a channel surface perpendicular to a (0001)-orientation plane.