Window glass heating device

A window glass heating device for a vehicle, comprising:

• a deicer configured to heat a whole area of a window glass of the vehicle to defog the window glass, wherein the deicer includes an electric heating wire disposed on the whole area of the window glass and defogs the window glass by heat generated from the electric heating wire;
• a first processor configured to control the deicer by turning on or off a deicer relay to supply power or cut off the supply of power to the electric heating wire when an on or off signal is input from a deicer switch operated by a user;
• a camera heater including a camera electric heating wire and a camera heater relay, wherein the camera heater heats a camera-imaging window area which is a part of the window glass included in an imaging area of a camera that images a vehicle exterior from a vehicle interior via the window glass, and a heating area of the camera heater being included in a heating area of the deicer;
• and
• a second processor configured to:
• acquire deicer operation information which is information on operation of the deicer including an operating time of the deicer,
• calculate an estimated temperature of the camera heater based on the deicer operation information, and
• control supply of power to the camera heater, by turning on or off the camera heater relay to supply power or cut off the supply of power to the camera electric heating wire, such that the estimated temperature of the camera heater is within a predetermined temperature range.