A focus adjustment apparatus that displays an in-focus state in a display region in association with control of a focus lens position. The apparatus includes a signal generation unit configured to output a pair of image signals from a focus detection region having a plurality of corresponding display regions, the image signals being generated by photoelectrically converting light having passed through an imaging optical system, and a control unit configured to detect a phase difference of the pair of image signals output from the focus detection region, and to control a position of the focus lens based on the phase difference detection result. The control unit detects the phase difference corresponding to divided regions formed by dividing the focus detection region, and displays an in-focus state in the display region in accordance with the control of the focus lens position control based on the phase difference detection result.