An image sensing unit with an improved structure and a digital camera adopting the same are provided. The image sensing unit for a digital camera includes a light-receiving surface having a plurality of pixel sensors arranged regularly on a two-dimensional region of a predetermined size, a scanning electronic circuit that outputs light incident onto the pixel sensors as an electric image signal that has undergone photoelectric conversion, and a color filter mosaic separated at a predetermined distance from the light-receiving surface in the light incidence direction. Here, the light-receiving surface is divided into a chromatic sensing element for receiving chromatic light entering through the color filter mosaic and the achromatic sensing element for receiving directly incident achromatic light that has not passed through the color filter mosaic. The digital camera adopting the image sensing unit can achieve smooth automatic focusing in a low brightness environment.