To provide a battery check circuit capable of correctly detecting the residual quantity of a battery of a camera in use.

A consumption current value PWR of an electronic camera in use is pre-stored in a ROM 29. A microcomputer 10 obtains the internal resistance RIN of the secondary battery 11 loaded on an electronic camera, and calculates the product (PWR × RIN) of this internal resistance RIN and the consumption current PWR. The microcomputer 10 compares the value subtracting the above product from a judgment threshold value VTH1 for judging wether or not the battery voltage is sufficient with a voltage value V2 of the battery 11 detected while the electronic camera is in use. The microcomputer 10 controls to turn on an LED 25 when the battery is maintaining a sufficient voltage and does not need to be replaced (recharged) but to flicker the LED 25 when the battery has a low voltage and needs to be replaced (recharged) before long.