A focus detection method, for detecting a focus state of an object image
in accordance with a contrast of the object image which is formed in a
focus detection area, includes capturing the object images while moving a
focusing lens group of a photographing lens stepwise within a
predetermined range of movement thereof; determining contrast values of
the plurality of object images in the focus detection area; and setting a
position of the focusing lens group as an in-focus position when a
contrast value, attained when the focusing lens group is positioned at
one of the closest focus position and the infinite-focus position or at a
position within a predetermined range of steps from the one of the
closest focus position and the infinite-focus position toward the other
of the closest focus position and the infinite-focus position, is at a
maximum contrast value.