A focus detection apparatus comprises: a reception unit configured to receive designation of a region within an image; a first setting unit configured to set one focus detection mode out of at least a first mode for performing focus detection with priority to a region of a subject and a second mode for performing focus detection with priority to the designated region; a second setting unit configured to set a focus detection region; a selection unit configured to select a region to focus on based on a focus detection result of the focus detection region; and a control unit, wherein the second setting unit, in the first mode, sets the focus detection region based on a result of a detection of a subject, and is the second mode, sets the focus detection region based on the designated region.