1. A target selection apparatus that selects a target from image data including a plurality of targets, comprising: a display control unit configured to display an image corresponding to the image data on a display unit; a drawing unit configured to draw a drawing line on the image displayed on the display unit; and a selection unit configured to select the target included in the image data based on the drawing line drawn by said drawing unit, wherein in response to the drawing line drawn by said drawing unit becoming a closed curve, the target selected by said selection unit is determined, and wherein said selection unit comprises: a region forming unit that, when the drawing line drawn by said drawing unit does not form the closed curve, sets a point on the drawing line to form a split detection region defined by a split line connecting a starting point of the drawing line and the point together and the drawing line; and a target detection unit that detects whether there is the target in the split detection region, wherein when the target is detected by said target detection unit, said display control unit displays the target on the display unit in a first display form, and when the drawing line becomes the closed line, said display control unit displays the target on the display unit in a second display form different from the first display form to determine the target.