To provide a pump drive control device configured to precisely detect the presence of water using a circulation pump of DC drive.

This pump drive control device comprises: a circulation pump 14 of DC drive for circulating hot water; and a control part 21 controlling the drive of the circulation pump 14. The control part 21 comprises: a speed command voltage part 22 applying a predetermined speed command voltage to the circulation pump 14; and a rotation speed detection part 23 for detecting the rotational speed of the circulation pump 14 after the application of the speed command voltage from the speed command voltage part 22. The control part 21 applies a predetermined first speed command voltage PV1 from the speed command voltage part 22 and a second speed command voltage PV2 higher than the first speed command voltage PV1 to the circulation pump 14. The rotational speed at that time is detected by a rotation speed detection part 23. A difference between two rotation speeds is compared with a predetermined value P1 stored in advance. A status determining operation is performed, in which, when it is equal to or more than the predetermined value P1, an idle operation is determined to inhibit the driving, and in which, when it is less than the predetermined value P1, the presence of a water current is determined to allow the driving.