SEAT HEATER

A seat heater includes first heat-generating elements 11-15 embedded in a seat so as to correspond to first sites of a seat occupant, second heat-generating elements 20, 21 embedded in the seat so as to correspond to second sites of the seat occupant, and a controller 3 for executing a fluctuation control in which a first set temperature of the first heat-generating elements 11-15 and a second set temperature of the second heat-generating elements 20, 21 are increased or decreased in each of a plurality of predetermined time periods. The controller 3 sets the first set temperature to be higher than the second set temperature in one of the time periods and sets the second set temperature to be higher than the first set temperature in another of the time periods.