To provide a power supply apparatus for informing surely a superfluous rise in temperature of a battery or a decrease in voltage value of the battery.

The power supply apparatus 2 for supplying electric power to electronic equipment includes: a battery holding unit 12 for holding batteries 16a-16d; a housing 4 equipped with an opening and a storing chamber for storing the battery holding unit 12; a battery cover 6 which can open and close the opening of the housing 4, at least one of a temperature detecting unit for detecting temperatures of the batteries 16a-16d or temperatures of places near the batteries 16a-16d and a voltage detecting unit for detecting voltages of the batteries 16a-16d; and display units 14a, 14b for displaying the detected result by at least one of the temperature detecting unit and the voltage detecting unit. At least one of the battery holding unit 12 and the battery cover 6 is a member which can be detached from and attached to the housing 4, and the temperature detecting unit, the voltage detecting unit, and the display units 14a, 14b are mounted on the member which can be detached and attached.