BELLOWS PUMP DEVICE

Provided is a bellows pump device that is able to reduce pulsation at a discharge side without causing a substantial increase in an installation space thereof and a decrease in a discharge amount thereof. The bellows pump device comprises: first and second bellows (13 and 14) mounted on a pump head (11) so as to be expandable/contractible independently of each other and configured to suck a fluid from a suction passage (34) thereinto by expansion thereof and discharge the fluid therefrom to a discharge passage (35) by contraction thereof; first and second air cylinder portions (27 and 28) configured to respectively cause the first and second bellows (13 and 14) to perform expansion/contraction operation; first and second detection devices (29 and 31) configured to detect expanded/contracted states of the first and second bellows (13 and 14), respectively; and a control unit 6 configured to control drive of the first and second air cylinder portions (27 and 28) on the basis of each of detection signals of the first and second detection devices (29 and 31) such that, before one bellows (13, 14) comes into a most contracted state, the other bellows (14, 13) is caused to contract from a most expanded state.