SEAT HEATER AND SEAT AIR-CONDITIONING DEVICE

A seat heater is installed between a seat pad that is a member supporting a load from a seated person sitting on a seat and has a plurality of ventilation holes through which the air generated by a blower flows is formed on a surface on a side of the seated person and a covering that covers a surface of the seat pad and has breathability. The seat heater includes a thin plate-like base material having voids through which air passes, and a heating wire fixed to the base material. A plurality of slits separate from the voids are formed in the base material.