A seat belt retractor for retracting a seat belt is formed of a first motor for retracting a seat belt with a force not providing a pressing feeling to a passenger, a second motor having a torque greater than that of the first motor for retracting the seat belt with a force forcibly holding the passenger to a seat, and a control circuit connected to the first and second motors for controlling the same. Thus, the seat belt retractor can perform a forced retraction and a normal retraction with an economical structure.