a motor driven camera has a power source , a motor connected to the power source and driven by the voltage of the power source , a constant voltage circuit for converting the voltage of the power source into a predetermined constant voltage and putting out the constant voltage , and an electric circuit connected to the constant voltage circuit and driven by the constant voltage circuit . the camera further has a battery checking device which includes a discriminating circuit for receiving the output of the constant voltage circuit and the output of the power source , comparing the two outputs and discriminating whether the voltage of the power source is above a predetermined level , and an indication circuit for receiving the output of the discriminating circuit and indicating the condition of the power source .