Semiconductor module cooler

Providing a cooler for a semiconductor module that can effectively cool the semiconductor element. Semiconductor module cooler supplies the cooling medium from the outside to the refrigerant jacket (2) to cool the fins semiconductor element disposed on the outer surface of the heat sink (1) with a (11) (13). The cooler refrigerant introduced from the outside, after spreading by the refrigerant diffusion chamber (26), to so as to overcome the refrigerant diffusion wall (25) cooling fin cooling chamber which is arranged fins (11) (28) is introduced, cooling the fins (11), it is discharged from the coolant outlet port (21) to the outside.