A semiconductor module solder bonding of high reliability in which the heat resisting properties of the circuit substrate and electronic parts are taken into consideration. In order to achieve this, there are provided semiconductor devices each having solder bumps as external pads, and a circuit substrate bonded to the external pads of each of the semiconductor devices through a solder paste, each of the solder bumps being made of a first lead-free solder, the solder paste being made of a second lead-free solder having a melting point lower than that of the first lead-free solder.