An electronic still camera includes a picture signal processing circuit and a compression processing circuit. A photographed picture signal is subject to compression processing in the compressing processing circuit after being processed in the picture signal processing circuit. Electric power supply from a power source circuit is controlled by a control circuit. Electric power is supplied only to the picture signal processing circuit at the time of picture processing, while electric power is supplied only to the compression processing circuit at the time of compression processing. In this way, electric power supply is controlled, resulting in savings of electric consumption and improving the picture quality.