A trip device for a circuit breaker, comprising: a crossbar rotatably installed to perform the trigger function; and a bimetal(150; 250; 350; 550) that is arranged to be curved upon the occurrence of an abnormal current and to press and rotate the crossbar by means of a gap adjustment member(160; 260; 360; 460; 560; 660), wherein the crossbar is movable in the length direction of a rotating shaft of the crossbar, characterised in that the gap adjustment member is attached to either the crossbar or the bimetal(150; 250; 350; 550) so that a contact surface of the gap adjustment member(160; 260; 360; 460; 560; 660) is parallel or non-parallel to the length direction of the rotating shaft, and if the contact surface of the gap adjustment member(160; 260; 360; 460; 560; 660) is non-parallel to the length direction of the rotating shaft, a gap between the contact surface of the gap adjustment member(160; 260; 360; 460; 560; 660) and a contact surface of the crossbar is adjusted depending on the position of the crossbar along the length direction of the rotating shaft, and if the contact surface of the gap adjustment member(160; 260; 360; 460; 560; 660) is parallel to the length direction of the rotating shaft, the gap between the contact surface of the gap adjustment member(160; 260; 360; 460; 560; 660) and the contact surface of the crossbar is kept constant regardless of the position of the crossbar along the length direction of the rotating shaft, wherein the gap adjustment member(160; 260) comprises: a side which is flat; and a rear side which is non-parallel to the side face, wherein the gap adjustment member(160; 260) is reversibly attached so that the side face becomes the contact surface, which is parallel to the length direction of the rotating shaft, of the gap adjustment member(160; 260) or the rear side becomes the contact surface, which is non-parallel to the length direction of the rotating shaft, of the gap adjustment member(160; 260). a crossbar rotatably installed to perform the trigger function; and a bimetal(150; 250; 350; 550) that is arranged to be curved upon the occurrence of an abnormal current and to press and rotate the crossbar by means of a gap adjustment member(160; 260; 360; 460; 560; 660), wherein the crossbar is movable in the length direction of a rotating shaft of the crossbar, characterised in that the gap adjustment member is attached to either the crossbar or the bimetal(150; 250; 350; 550) so that a contact surface of the gap adjustment member(160; 260; 360; 460; 560; 660) is parallel or non-parallel to the length direction of the rotating shaft, and if the contact surface of the gap adjustment member(160; 260; 360; 460; 560; 660) is non-parallel to the length direction of the rotating shaft, a gap between the contact surface of the gap adjustment member(160; 260; 360; 460; 560; 660) and a contact surface of the crossbar is adjusted depending on the position of the crossbar along the length direction of the rotating shaft, and if the contact surface of the gap adjustment member(160; 260; 360; 460; 560; 660) is parallel to the length direction of the rotating shaft, the gap between the contact surface of the gap adjustment member(160; 260; 360; 460; 560; 660) and the contact surface of the crossbar is kept constant regardless of the position of the crossbar along the length direction of the rotating shaft, wherein the gap adjustment member(160; 260) comprises: a side which is flat; and a rear side which is non-parallel to the side face, wherein the gap adjustment member(160; 260) is reversibly attached so that the side face becomes the contact surface, which is parallel to the length direction of the rotating shaft, of the gap adjustment member(160; 260) or the rear side becomes the contact surface, which is non-parallel to the length direction of the rotating shaft, of the gap adjustment member(160; 260). a side which is flat; and a rear side which is non-parallel to the side face, wherein the gap adjustment member(160; 260) is reversibly attached so that the side face becomes the contact surface, which is parallel to the length direction of the rotating shaft, of the gap adjustment member(160; 260) or the rear side becomes the contact surface, which is non-parallel to the length direction of the rotating shaft, of the gap adjustment member(160; 260).