Abstract: A flexible diaphragm having an arcuate ridge defines the pumping chamber of a fluid pump and is reciprocated by connection to the output shaft of an electric motor. The rigid plate portion of a connector is joined to the central portion of the diaphragm while the remainder thereof extends in an opposite direction where it is linked with an eccentric coupling carried by the output shaft of the motor. Although the diaphragm is driven in a rocking, reciprocating movement, the housing is formed with surface support portions which have radii of curvature such as to support the diaphragm during its distended periods, thereby assuring a long lifetime of diaphragm operation. The overall arrangement results in improved efficiency in pumping gases as well as liquids.