Liquid heater

A liquid heater comprising:

• a heat intended liquid flow channel having a first and second wall through which heat intended liquid flows in a liquid flow direction with the first wall being an inner wall and the second wall being an outer wall relative to a heating part
• disposed facing the first wall of the heat intended liquid flow channel for radiating heat toward the heat intended liquid flow channel so that a heat radiation direction crosses the liquid flow direction;
• a heat reflecting part having one side thereof facing the second wall of the heat intended liquid flow channel on a side opposite the first wall and at a location separated and spaced apart from said second wall of the heat intended liquid flow channel such that no direct thermal conduction exists between the heat reflecting part and said second wall of the heat intended liquid flow channel;
• a cooling part that cools the heat reflecting part,
• wherein the cooling part includes a cooling medium flow channel through which a cooling medium flows with the cooling medium flow channel facing the heat reflecting part on a side thereof opposite said one side of the heat reflecting part and being disposed in a substantially common direction with the longitudinal direction of the heat intended liquid flow channel for cooling the heat reflecting part by the cooling medium, and
• an outer cooling medium flow channel connected to an introduction side and a discharge side of the cooling medium flow channel with the outer cooling medium flow channel corresponding to the discharge side provided with a second cooling part that cools the cooling medium.