A fuel supply pump with a large fuel discharge amount and a tappet structure body, which are suitably used for an accumulated pressure-type fuel injection device that mechanically amplifies pressure, is provided. A fuel supply pump has a tappet structural body and a spring sheet, wherein a penetration portion for allowing passage of a lubricant or a fuel for lubrication therethrough by coordinating the tappet structure and the spring sheet is provided between a spring-holding chamber for holding a spring to be used for pulling up a plunger and a cam chamber for housing a cam to be used for moving the plunger up and down.