To make it possible to perform focusing correctly and easily at the time of low luminance.

When the digital camera is set to a low luminance focusing mode, the digital camera performs prephotographing a plurality of times continuously while moving focusing optical system by the prescribed pitch, and images obtained by each prephotographing are stored being associated with positions of the focusing optical system in prephotographing and each of the stored photographed images is displayed on a display device. A photographer selects an image whose focused state is the best from among displayed images. When the image is selected, the focusing optical system is driven to a position which is stored by being associated with the selected image. Moreover, when the camera itself extracts an image whose focusing state is the best and shows it clearly, it serves as a reference on the selection of the image by the photographer.