An apparatus for detecting an edge crack of a metal plate being conveyed includes: a detection part including a plurality of elements configured to detect a presence or absence of the metal plate at a position of the element in the plate width direction; a plate edge position determination part configured to determine a plate edge position of the metal plate in the plate width direction on the basis of a detection result of each of a plurality of first elements positioned within a first region in the plate width direction; and an edge crack detection part configured to detect an edge crack of the metal plate on the basis of a detection result of each of a plurality of second elements selected on the basis of the plate edge position and positioned within a second region which is narrower than the first region in the plate width direction.