An AF controller includes: a signal generator configured to generate an image signal pair for each of a plurality of areas in an imaging angle of view; a target position deriver configured to derive a driving target position of a focus lens based on a defocus amount derived by the image signal pair input from the signal generator and based on an acquired position of the focus lens; and a driving command unit configured to output a driving command of the focus lens based on the driving target position, wherein the driving command unit outputs the driving command of the focus lens based on the driving target position in a range of a threshold.