The power semiconductor module

A power semiconductor module (10) having an integral circuit board (11) with a metal substrate electrode (14), an insulation substrate (15) and a heat sink (12) joined is disclosed. A Sic semiconductor power device (13) is joined to a top of the metal substrate electrode of the circuit board. A difference in average coefficients of thermal expansion between constituent materials of the circuit board in a temperature range from room to joining time temperatures is 2.0 ppm/ DEG C or less, and a difference in expansion, produced by a difference between a lowest operating temperature and a joining temperature, of the circuit-board constituent materials is 2, 000 ppm or less.