Seat belt system

A seat belt system having a reversible pretensioner 30 for forcibly driving a seat belt 14 in a tightening direction so as to restrain an occupant in a seat 13, a control section for controlling the pretensioner, and a rear-end collision detecting section 49 for detecting the occurrence of a rear-end collision of a vehicle and outputting a rear-end collision detection signal in the event of detection of the occurrence of a rear-end collision, wherein the control section causes the pretensioner 30 to drive the seat belt 14 in the tightening direction in the event that a rear-end collision detection signal is outputted from the rear-end collision detecting section.