HIGH-PRESSURE FUEL SUPPLY PUMP

Provided is a high-pressure fuel supply pump that maintains oil-tight performance even when the fuel pressure is high, and includes a small and lightweight discharge valve structure. The structure prevents the reduction in oil-tight performance caused by the deformation of the seat part due to the high back pressure that the discharge valve receives. The structure also makes the provision of a flow path compatible with the size reduction and weight reduction of the discharge valve. The valve body of the discharge valve includes a guide part and a curved contact surface. Thus, the seat part is formed with Hertzian contact and this formation exerts high oil-tightness even when a high back pressure is applied to the valve body. The guide part is provided to the valve body. This provision determines the position of the curved contact surface. This determination reduces the size and weight of the valve body.