COOLANT HEATER

The present invention relates to a coolant heater. The purpose of the present invention, a coolant heater which effectively heats coolant of a vehicle by means of a heating unit, is to provide a coolant heater having improved sensitivity and responsiveness to over-heating and assured stability by utilizing a temperature fuse to prevent over-heating. Another purpose of the present invention is to provide a coolant heater having enhanced durability of the temperature fuse coupling part by improving the structure by which the temperature fuse is fixed.