A pump control mechanism includes a pump unit for feeding liquid to container, a position detector for detecting the position in the reciprocating motion of the pump member, a control table having control information of many time zone sections, an information memory for storing target information corresponding to a target driving speed, a driving information calculator for calculating driving information of a motor on the basis of the reciprocating position detection, a correcting information calculator for calculating correction information for reducing the difference between the driving information and the target information, and a corrector for correcting the control table. The control table has individual control information for each of time zone sections for increasing/reducing the driving force in accordance with the magnitude of the load of the motor, and a control information increasing section for locally increasing the driving force in connection with a case where a large load locally acts on the motor exists in the control table.