Focus detection apparatus and control method therefor

A focus detection apparatus includes an image pickup unit configured to perform photoelectric conversion on a luminous flux having passed through an imaging optical system, a focus detection unit configured to detect a focusing state based on a signal generated by the image pickup unit, a setting unit configured to set a first region within an image generated by the image pickup unit, a display controller configured to control such that an index representing the focusing state detected by the focus detection unit within the first region can be superimposed on the image, and an obtaining unit configured to obtain information regarding a predetermined subject in the image. In this case, the setting unit sets a position of the first region based on information regarding at least one of a position, a size, and a direction of the predetermined subject in the image.