An imaging device includes an optical system, an image sensor, a lens position control section, and a focus control section, the focus control section including a block setting section, a contrast value calculation section that calculates block contrast value information, a contrast value storage section that stores the block contrast value information about a reference image, a feature quantity calculation section, an effective block determination section that acquires effective block information, an effective block information storage section that stores the effective block information about the reference image, an AF area setting section that sets an AF area from the effective block information about the reference image and the effective block information about the input image, and a contrast value determination section that determines an image contrast value from the AF area.
