A coolant cooled type semiconductor device capable of achieving a superior heat radiation capability is provided, while having a simple structure. While a plurality of semiconductor modules are arranged in such a manner that main surface directions of these semiconductor modules are positioned in parallel to each other in a interval along a thickness direction thereof. These semiconductor modules are sandwiched by coolant tube having folded portions with fixing members. As a consequence, both surfaces of the semiconductor module can be cooled by a single coolant tube with a uniform pinching force.