A filament lamp and light irradiation type heat treatment device capable of uniformly thermally processing the entirety of an article to be treated has a filament lamp (100) in which coil-shaped filaments are disposed along the tube axis within a light emitting tube (102), wherein the filaments are electrically connected to a low-emission coil (F2″) having a relatively smaller effective surface area and to high-emission coils (F1″, F1″) having relatively large effective surface areas, with the low-emission coil disposed in between in the axis of the tube direction, and a light irradiation type heat treatment device utilizing the filament lamp (100).