Abstract: A reciprocating type fluid delivery pump has a driving motor, plungers for driving two pump heads, respectively, and a converting mechanism for converting the rotational motion of the driving motor into a reciprocating motion of each plunger. The converting mechanism includes a cam having such a configuration that, when the driving motor is rotated at constant velocity, the delivery flow rate during the delivery starting period of each of the plungers is in excess of that during the other periods of the cycle. The speed of rotation of the driving motor is reduced during the excess delivery period according to need. Thus, the load on the driving motor is reduced and it is therefore possible to employ a driving motor having a relatively low output. The delivery pump also includes a rinsing chamber for each plunger for allowing pressurized fluid to pass therethrough. The rinse chamber includes a rinse pump which uses the reciprocal movement of the pump piston for the rinse mechanism.