A semiconductor device comprises a semiconductor element which is flip-chip bonded to a circuit substrate. The semiconductor element and the circuit substrate are flip-chip bonded using a sealing resin having flux function. The semiconductor element includes a solder bump formed on a first electrode pad through a first low melting point solder layer. The circuit substrate includes a second electrode pad corresponding to the first electrode pad, and a second low melting point solder layer is formed on the second electrode pad. The solder bump is bonded to the first and second electrode pads through the first and second low melting point solder layers.