PURPOSE: To warm the body such as legs without arranging a heater into the bedding, etc. by forwarding air heated into space hermetically sealed approximately by a heat insulating material such as the bedding by means of a fan, etc.

CONSTITUTION: When a person goes to bed while a coverlet 3 is put on a mattress 2, air 5 heated is injected at his feet from the bottom of the bedding 2, 3 by means of a nozzle 6 from a warm-air instrument 4, and forwarded into space between the bedding 2, 3 hermetically sealed approximately. The warm-air instrument 4 consists of a fan section 7 taking in the outside air, a ceramic heater 8, a duct 9 and the flat nozzle 6, which is fitted to the nose of the duct 9 and laterally extended.