PURPOSE: To extend the life time of a battery, by providing a control means performing different state informations by an information means on the basis of the detection signals from a plurality of low battery detection circuits.

CONSTITUTION: Low battery circuits 10AW10C are provided to electronic equip ment. The circuit 10A converts the port LB1 of CPU 5 from L-level to H-level when power source voltage VP reaches reference voltage VLB1 or less and CPU 5 outputs a low battery alarm state to a display device to indicate the replace ment of a battery. In this state, it is ensured that each apparatus operates as usual. Further, when the electronic machinery is used by the judgement of a user, the voltage VP drops and, when said voltage VP becomes reference voltage VLB2 or less, the circuit 10B sets the port LB2 of CPU 5 to H-level to output a low battery dangerous state to the display device to perform error display and CPU 5 immediately interrupts al of processings. When power source voltage VCC reaches reference voltage VLB3 or less, the circuit 10C sets the port LB3 of CPU 5 to H-level and CPU 5 performs error processing.