A digital camera, in which power supply to a display screen constituted by an LCD is ON/OFF-controlled, is disclosed. When drive power is supplied to the LCD, an object image is displayed on the LCD based on image data obtained by image pickup, and the LCD is used as a viewfinder in photographing. At this time, when a period, in which the level of the brightness of the object image expressed by a luminance signal of the image data is less than a predetermined level, continues for a predetermined period or longer, the supply of the drive power to a display system including the LCD is controlled to stop the supply of the drive power and save power consumption.