PURPOSE: To improve the operational reliability of a circuit using constant voltage as a power supply by supplying each circuit with constant voltage respectively independently by separate wiring.

CONSTITUTION: A constant voltage circuit generating constant voltage is connected to a constant-voltage output terminal 6 by a metallic wiring 1, and a capacitor 9 is connected to the constant-voltage output terminal 6 by external mounting. In this case, the metallic wiring 1 is used only with the object of the connection of the constant voltage circuit and the constant-voltage output terminal, and a metallic wiring 2 is employed with the object of the connection of the constant-voltage output terminal and a quartz oscillation circuit. The metallic wiring 2 is used only with the object of the bonding of the constant- voltage output terminal and the quartz oscillation circuit in the same manner as the metallic wiring 1. A metallic wiring 3 bonds the constant-voltage output terminal and the CR oscillation circuit of high frequency. Metallic wirings 4, 5 are employed for connecting a timer and a CPU as circuits at functional units and the constant-voltage output terminal respectively. The constant voltage of the quartz oscillation circuit is taken by a wiring separated from the constant-voltage circuit output terminal, thus acquiring stabilized potential.