To provide an exposure controller and an exposure control method to control to a target exposure value with high responsiveness and at high accuracy in a wide range of exposure adjustment.

An exposure controller uses an exposure evaluation value EV (pv) and a target exposure value EV (sp) in a luminance signal to control an exposure in an exposure adjustment range ER by plural exposure adjustment parts. A deviation EV (err) is obtained between the target exposure value EV (sp) and the exposure evaluation value EV (pv). When the deviation EV (err) is smaller than a predetermined value within a normal state and the exposure is controlled within a gain exposure control range ER-g, a gain exposure adjustment part 62 controls the exposure by a main control amount Ci-m and a diaphragm exposure adjustment part 61 also adds a diaphragm correction amount Ci-s.