A mechanism for reducing pressure pulsation includes a pair of metal dampers formed by joining two disk-shaped metal diaphragms over an entire circumference and forming a hermetically sealed space inside a joined portion, with gas being sealed in the aforementioned hermetically sealed space of the damper, has a pair of pressing members which give pressing forces to both outer surfaces of the aforementioned metal dampers at a position at an inner diameter side from the joined portion, and is unitized with the pair of pressing members being connected in a state in which they sandwich the metal damper.