To provide a detachable temporary power supply for a cellular phone, capable of attaining calling of a very long time, even with a high power consuming cellular phone, attaining calling for an extremely long time which is several times as long as the conventional built-in power supplies, and charging the built-in battery of the cellular phone.

This detachable temporary power supply for the cellular phone consists of a power supply 1 such as an alkaline battery, a diode 3, a regulator 4, and a connector 2. The voltage, supplied from the power supply 1, can be achieved by the temporary power supply including a feeder circuit which supplies a constant voltage through the regulator 4 and prevents reverse flow of the current from the built-in battery of the cellular phone.