The present invention provides a fuel supply system having improved assembly and pulsation reducing efficiency. A housing (20) of a fuel supply system (1) is formed by joining a first housing member (20a) forming one end side of a tubular chamber (23) in the direction of the backward and forward movement of a plunger (10) and a second housing member (20b) forming the other end side. A pulsation reducing mechanism (60) includes a tubular bellows damper (61) housed in the tubular chamber (23).