A temperature environment regulating system includes an in-vehicle temperature conditioner, a thermal sensation estimating section, a preference estimating section, a preference memory section, and a control section. The in-vehicle temperature conditioner regulates passenger-compartment temperature environment in a vehicle. The thermal sensation estimating section estimates thermal sensation, which is an indicator representing how the user senses in-vehicle temperature environment. The preference estimating section estimates temperature preference of the user based on a temporal change in the thermal sensation. The control section controls the in-vehicle temperature conditioner based on the temperature preference memorized by the preference memory section.