Abstract: A seat heater includes a base sheet, a plurality of sheet heating elements disposed on the base sheet, and two sheet electrodes coupled to each of the sheet heating elements. Each of the sheet heating elements has a rectangular shape with a long side of not more than 9 cm and a short side of not more than 5 cm. Each of the sheet electrodes is disposed on each of the sheet heating elements substantially along the entire short side of the sheet heating element.