A heater control device includes a current calculating unit (20) which calculates a third value of current based on a first value of current flowing through a first PTC element of a first PTC heater which is in an energized state and a second value of current estimated to flow through a second PTC element of a second PTC heater which is to be newly put into an energized state next, and a switching control unit (21) which maintains a non-energized state of the second PTC element of the second PTC heater until it is determined that the third value of current calculated by the current calculating unit (20) is less than a predetermined maximum allowable value of current and puts the second PTC element of the second PTC heater into an energized state when the third value of current is less than the predetermined maximum allowable value of current.