The object of the present invention is to provide a bellows pump which is able to accurately pump out a fixed amount of fluid, even with the fluid of high temperature with granular bits included. The bellows pump 3 is comprised of bellows 20 formed in a shape of accordion, nozzles 30u and 30d arranged at the both ends of the bellows 20, and check valves 40u and 40d arranged at the fluid-flow-inlet 23u and fluid-flow-outlet 23d at the both ends of the aforementioned bellows 20 respectively, wherein each of the aforementioned check valves 40u and 40d is comprised of a valve base 41 with its downstream surface concaved with more than one holes pierced through it, a valve body 44 made of elastic thin body which is fixed to the downstream surface 41b of the aforementioned valve base 41 with a hole 46 formed at its center for allowing the flow of the fluid, and a pressing element 47 which adds pressure to the aforementioned valve body 44 allowing it to be compressed against the downstream surface of the aforementioned valve base 41, and aforementioned valve body 44 adheres closely to the downstream surface 41b of the aforementioned valve base 41 by the pressing force of the aforementioned pressing element 47.