A semiconductor memory integrated circuit is made up of a decoder, a memory matrix, and a decode output buffer selectively receiving a first or second power source voltage. The decode output buffer is provided between the decoder and the memory matrix, and includes an inverter circuit for inverting the output signal of the decoder, and a MOS transistor of a depletion mode, the gate of which is connected to the output terminal of the inverter, the first end of which is connected to a supply node of the first or second power source voltage, and the second end of which is connected to a power voltage supply node of the inverter circuit.