PURPOSE: To provide a safe and easy heating of an item to be heated with a high thermal efficiency by a method wherein an optical fiber collecting far infrared beam radiated from a source of generating far infrared beam with a light collector device and for transmitting the beam and a dispersion device for dispersing the transmitted far infrared beam around its surroundings are provided.

CONSTITUTION: A far infrared beam 12 generated from a far infrared beam gas burner 11 passes through a heat-resistant glass 13 for keeping safety, is converged to a focus by a beam collector plate 14 of aluminum with a concave surface having a high efficiency of reflection and is converged by a lens 15 placed at a focusing position in the beam collecting plate 14. The converged far infrared beam is transmitted to a far infrared beam dispersing position by an optical fiber 16 and reached to a dispersion lens 17. The reached far infrared beam is dispersed from the dispersion plate 18 of aluminum plate having a concave surface with a focus point of the position of the dispersion lens 17 in an upward direction. In this way, the far infrared beam is applied as a heating source and at the same time the far infrared beam is transmitted to the heat utilizing position with the optical fiber and dispersed there, it is made possible to receive heat from the far distant heating source and to provide a safe and easy heating of the item to be heated under a high thermal efficiency.