FUEL SUPPLY PUMP

Provided is a fuel supply pump capable of improving welding quality while securing a function of a valve body. A fuel supply pump of the present invention includes a regulating member (discharge valve stopper ) that guides movement of a valve body (discharge valve ), a main body portion (body ) provided with a valve chamber (discharge valve chamber ) that houses the regulating member, a sealing member (plug ) that seals the valve chamber, and a welded portion (welded portion ) that fixes the sealing member to the main body portion. An annular space portion (annular space portion ) along an outer periphery of the regulating member is formed between the welded portion and the regulating member. The regulating member includes a positioning portion (fitting portion ) for positioning with respect to the main body portion on a side opposite to the sealing member, and a gap forming portion (gap forming portion ) forming an annular gap (annular gap ) between the gap forming portion and the main body portion, and the annular gap allows a space on a side of the positioning portion in the valve chamber and the annular space portion to communicate with each other.