According to LSI packages of the BGA type and the like, the number of source voltage supply terminals on an LSI package needs to be around the same as the number of power supply terminals on an LSI chip, in order to prevent the impact of high-frequency currents generated due to a switching operation in an internal circuit in the LSI chip. According to the present invention, however, at least two power supply terminals on an LSI chip are connected to one source voltage supply terminal on an LSI package. In addition, a capacitor element is embedded in a substrate forming the main body of the LSI package, and the capacitor element is provided between a source voltage supply terminal and an earth terminal.