The present application relates to a pad-temperature regulating apparatus for regulating a temperature of a surface of a polishing pad. The pad-temperature regulating apparatus includes a pad-contact member, a supply system for supplying a heating liquid and a cooling liquid into the pad contact member, a pad-temperature measuring device for measuring the temperature of the surface of the polishing pad, and a controller for performing a PID control of manipulated variables of a first flow control valve and a second flow control valve. The controller includes a memory in which a learned model constructed to maintain a temperature behavior curve, created based on measured values of the pad-temperature measuring device, within a predetermined allowable range, is stored; and a processing device which inputs at least one temperature behavior parameter to the learned model, and performs a calculation to output a change value of PID parameter for the PID control.