A toy gun comprising a device for attachment-detachment of a slide, comprising: a slide disposed at an upper part of the toy gun body while covering a barrel, and slidingly moving toward a muzzle of the barrel, and toward a rear end side of the toy gun; a takedown lever disposed on a surface of the toy gun body at a boundary with the slide, the takedown lever being rotatingly movable along the surface of the toy gun body; a takedown link having one end attached to an inner side of a top end of the takedown lever; a link convex portion attached to the other end of the takedown link, wherein the link convex portion is convexly attached to an inner side of a mechanical frame of the toy gun; a crank and a crank groove formed in a center of the crank in a longitudinal direction, wherein the link convex portion is engaged with and guided by the crank groove; and a slide block crank that comes in contact with a part of the slide or a part connected to the slide directly or indirectly to prevent the slide from moving toward the rear side of the gun, and moves in a muzzle direction and a non-muzzle direction accompanying with the rotating movement of the takedown lever, the slide block crank being closer to the muzzle in moving in the muzzle direction than in moving in the non-muzzle direction, wherein the crank and the slide block crank are connected forming a V-like shape, wherein the crank and the slide block crank in connection with each other are attached to the mechanical frame at the connected portion using a crank shaft, wherein the crank and the slide block crank are rotatable around the crank shaft, wherein through rotation of the takedown lever, the link convex portion attached to the top end of the takedown link is engaged with the crank groove formed in the crank so that the crank is rotated, such that the slide block crank oppositely attached via the crank shaft rotates in the opposite direction. a slide disposed at an upper part of the toy gun body while covering a barrel, and slidingly moving toward a muzzle of the barrel, and toward a rear end side of the toy gun; a takedown lever disposed on a surface of the toy gun body at a boundary with the slide, the takedown lever being rotatingly movable along the surface of the toy gun body; a takedown link having one end attached to an inner side of a top end of the takedown lever; a link convex portion attached to the other end of the takedown link, wherein the link convex portion is convexly attached to an inner side of a mechanical frame of the toy gun; a crank and a crank groove formed in a center of the crank in a longitudinal direction, wherein the link convex portion is engaged with and guided by the crank groove; and a slide block crank that comes in contact with a part of the slide or a part connected to the slide directly or indirectly to prevent the slide from moving toward the rear side of the gun, and moves in a muzzle direction and a non-muzzle direction accompanying with the rotating movement of the takedown lever, the slide block crank being closer to the muzzle in moving in the muzzle direction than in moving in the non-muzzle direction, wherein the crank and the slide block crank are connected forming a V-like shape, wherein the crank and the slide block crank in connection with each other are attached to the mechanical frame at the connected portion using a crank shaft, wherein the crank and the slide block crank are rotatable around the crank shaft, wherein through rotation of the takedown lever, the link convex portion attached to the top end of the takedown link is engaged with the crank groove formed in the crank so that the crank is rotated, such that the slide block crank oppositely attached via the crank shaft rotates in the opposite direction.