Comfortable sensation of living bodies is estimated, considering individual differences in biological information on the living bodies staying or residing in a common space, and stimulation contents is properly controlled. A stimulation generator generates a stimulation to be applied to users. Biological information acquirers and acquire time-series data of biological information on the users. Parameter extractors and extract a parameter which is changed with a lapse of time by analyzing the time-series data. Thermal sensation estimators and estimate statuses of the users to the stimulation generated by the stimulation generator, based on the parameter extracted by the parameter extractors and. A multi-user thermal sensation processor integrates estimation results on the users estimated by the thermal sensation estimators and into a single estimation result. A stimulation controller controls the stimulation generator based on the integrated estimation result.