A semiconductor module includes a refrigerant jacket including a refrigerant passage through which a refrigerant circulates and an opening extending from an outer surface to the refrigerant passage, a base mounted on the refrigerant jacket and closing the opening, and a semiconductor element provided at the base. The base includes an annular peripheral wall positioned inside the opening, a bottom plate connected to an end portion of the peripheral wall on a side closer to the refrigerant passage, and a fin protrusion protruding from the bottom plate toward the inside of the refrigerant passage and formed on the bottom plate. The base has a recess formed with the peripheral wall and the bottom plate and extending toward the opening. The semiconductor element is disposed on the bottom plate inside the recess.