A retracting device, comprising: a retracting main body (6, 6A) including a case (1, 1A) for placing on an enclosure side, a hook disposed in the case (1, 1A), an urging member, and a braking device; and a protruding portion for placing on a moving body side, and engaging with and disengaging from the hook in a middle of a movement of a moving body relative to an enclosure, wherein the hook is switched between a retracting position allowing the moving body to move in an engaged state with the protruding portion, and a standby position prohibiting the moving body to move in a disengaged state, wherein the braking device includes a piston damper having a cylinder and a piston rod, and either one of the cylinder or the piston rod is fixed in the case side, and the other is slidably disposed and the hook is pivotally supported on an end side thereof, and the hook is in the standby position in which the hook is disengaged from the protruding portion in a state wherein the piston rod is entered with respect to the cylinder to reduce a protruding dimension and is switchable to the retracting position from the standby position when the piston rod increases the protruding dimension relative to the cylinder, wherein the urging member includes a compression spring, and is disposed along the piston damper, and one end is locked on a slidably disposed side among the cylinder and the piston rod, and the other end is immovably engaged, characterized in that the retracting device further comprises a guide axis connected to the other slidably disposed side among the cylinder and the piston rod, and disposed approximately parallel to the piston damper, wherein the compression spring is disposed on an outer circumference of the guide axis. a retracting main body (6, 6A) including a case (1, 1A) for placing on an enclosure side, a hook disposed in the case (1, 1A), an urging member, and a braking device; and a protruding portion for placing on a moving body side, and engaging with and disengaging from the hook in a middle of a movement of a moving body relative to an enclosure, wherein the hook is switched between a retracting position allowing the moving body to move in an engaged state with the protruding portion, and a standby position prohibiting the moving body to move in a disengaged state, wherein the braking device includes a piston damper having a cylinder and a piston rod, and either one of the cylinder or the piston rod is fixed in the case side, and the other is slidably disposed and the hook is pivotally supported on an end side thereof, and the hook is in the standby position in which the hook is disengaged from the protruding portion in a state wherein the piston rod is entered with respect to the cylinder to reduce a protruding dimension and is switchable to the retracting position from the standby position when the piston rod increases the protruding dimension relative to the cylinder, wherein the urging member includes a compression spring, and is disposed along the piston damper, and one end is locked on a slidably disposed side among the cylinder and the piston rod, and the other end is immovably engaged, characterized in that the retracting device further comprises a guide axis connected to the other slidably disposed side among the cylinder and the piston rod, and disposed approximately parallel to the piston damper, wherein the compression spring is disposed on an outer circumference of the guide axis.