An autofocus lens apparatus is disclosed which is capable of changing a focus target area in position and size without degrading the operability of manual focusing when taking images with an autofocus function. The autofocus lens apparatus comprises an operating member which is placed outside a lens barrel and movable to change the focus target area, a detector which detects the movement of the operating member, and a controller which changes at least one of the position and size of the focus target area on the basis of a signal from the detector.