A power transmission device comprising: a primary pulley that is formed of a fixed sheave and a movable sheave; a secondary pulley that is formed of a fixed sheave and a movable sheave; a looped transmitting member that is looped over the primary pulley and the secondary pulley; a casing that accommodates the primary pulley, the secondary pulley and the looped transmitting member; and a tubular stabilizer which is arranged between the primary pulley and the secondary pulley, and through which a string portion of the looped transmitting member is passed so as to be movable relative to the stabilizer whereby movement of the looped transmitting member is restricted, wherein the stabilizer is supported by the looped transmitting member and is moved in a traveling direction of the looped transmitting member as the looped transmitting member moves in the traveling direction, and wherein a movement of the stabilizer of which an amount is equal to or larger than a predetermined amount is restricted by a restricting device, wherein the restricting device includes a fixing stopper that is fitted to the casing, a first rib that is fixed to a tubular body of the stabilizer and that contacts the fixing stopper during forward rotation to restrict a travel range of the stabilizer, and a second rib that is fixed to the tubular body of the stabilizer and that contacts the fixing stopper during reverse rotation to restrict a travel range of the stabilizer, characterized in that the stabilizer is provided with a shock absorbing member (31, 34) that absorbs a shock in the event of a contact with the fixing stopper, or the fixing stopper is provided with a shock absorbing member (41, 42, 43) that absorbs a shock in the event of a contact with the stabilizer. a primary pulley that is formed of a fixed sheave and a movable sheave; a secondary pulley that is formed of a fixed sheave and a movable sheave; a looped transmitting member that is looped over the primary pulley and the secondary pulley; a casing that accommodates the primary pulley, the secondary pulley and the looped transmitting member; and a tubular stabilizer which is arranged between the primary pulley and the secondary pulley, and through which a string portion of the looped transmitting member is passed so as to be movable relative to the stabilizer whereby movement of the looped transmitting member is restricted, wherein the stabilizer is supported by the looped transmitting member and is moved in a traveling direction of the looped transmitting member as the looped transmitting member moves in the traveling direction, and wherein a movement of the stabilizer of which an amount is equal to or larger than a predetermined amount is restricted by a restricting device, wherein the restricting device includes a fixing stopper that is fitted to the casing, a first rib that is fixed to a tubular body of the stabilizer and that contacts the fixing stopper during forward rotation to restrict a travel range of the stabilizer, and a second rib that is fixed to the tubular body of the stabilizer and that contacts the fixing stopper during reverse rotation to restrict a travel range of the stabilizer, the stabilizer is provided with a shock absorbing member (31, 34) that absorbs a shock in the event of a contact with the fixing stopper, or the fixing stopper is provided with a shock absorbing member (41, 42, 43) that absorbs a shock in the event of a contact with the stabilizer.