To prevent such troubles in a pressure type electromagnetic pump, that even when the base valve of an oil tank is closed when an oil water heater or the like is not used, a fuel in a sealed flow passage in the upstream side of an electromagnetic valve thermally expands by rising of the ambient temperature to increase the pressure, which induces oil-tight breakage in the fuel flow passage.

The pressure type electromagnetic pump performs cooperative pumping action of a piston 21 driven by an electromagnetic plunger 15 with an intake vale 28 and a discharge valve 29. In the pressure type electromagnetic pump, an electromagnetic valve 50 and a valve seat 70 are disposed in a fluid passage running from the discharge valve 29 to a discharge port 87. The electromagnetic valve 50 is energized by an electromagnetic valve spring 51. The valve seat 70 is provided so as to be slidable in a large-diameter part 73 with a member 62 constituting the fluid passage, and is energized by a valve seat spring 76. The electromagnetic valve 50 is then seated in the small-diameter part 72 of the valve seat 70. The small-diameter part 72 is disposed in the electromagnetic valve side, and a gap passage 79 is constituted between the small-diameter part 72 and the member 62 constituting the flow passage, and an accumulator 82 is connected to the gap passage 79.