A temperature adjustable seat is disclosed. The temperature adjustable seat comprises a seat and air being blown into an inside thereof a thermoelectric device for heating and cooling the air, an air-blower for blowing either heated air or cooled air by the thermoelectric device through the inside of the seat, and control device for controlling the thermoelectric device. The control device calculates a required heat quantity, the required heat quantity being a sum of a first heat quantity required for a seat surface temperature of the seat reaching to a target seat temperature and a second heat quantity that is given and received between the seat and an ambient environment and the control device controls a temperature of the thermoelectric device so as to supply the required heat quantity to the seat.