A reciprocating pump capable of reducing its overall size by suppressing the size of an entire drive unit. A plurality of piston parts move in the same direction and draw fluid into a plurality of pump chambers and discharge the fluid. The pump chambers are adjacent to each other. A motor has a drive shaft between the centers of piston parts located at both ends in the installation direction of the pump chambers and oriented in a direction substantially orthogonal to the installation direction of the pump chambers and substantially orthogonal to the moving direction of the piston parts. A plurality of cams are aligned adjacent each other in the axial direction on the motor drive shaft. The cams are linked to the piston parts so that the cams cause the reciprocal movement of the piston parts.