Power semiconductor unit, power module, production method for power semiconductor unit and production method for power module

A heat radiating surface (7b, 8b) of an electrode lead frame (7, 8) is in thermal contact with a heat radiating member (301) through an insulation sheet (10) and the heat from a power semiconductor element (5) is radiated to the heat radiating member (thick walled part (301)). Either an exposed region of the heat radiating surface (7b, 8b) or the surface (13b) of a mould member (sealant (13)), which is in contact with said exposed region, protrudes and forms an irregular step. The step profile formed between the surface of the protruding side and the surface of the recessed side of the irregular step is formed with inclined surfaces (7a, 13a) in such a manner that the angle with the surface of the protruding side and the angle with the surface of the recessed side are each obtuse.