An energization control device for a glow plug adapted to be connected between a power supply for supplying electric power to a plurality of glow plugs mounted on an engine and the glow plugs and adapted to control the energization of the glow plugs, comprising: a glow plug connection portion to which the plurality of glow plugs are electrically connected in parallel; a voltage obtaining section adapted to obtain at least one of a voltage supplied from the power supply and a voltage output from the glow plug connection portion; a current obtaining section adapted to obtain a current output from the glow plug connection portion to the glow plugs; an energization state determination section adapted to determine the state of energization of the glow plugs; a threshold value setting section adapted to set a threshold value used for wire breakage determination, wherein the threshold value is set for a specific energization state determined by the energization state determination section; a resistance obtaining section adapted to obtain a combined resistance of the glow plugs connected to the glow plug connection portion on the basis of the voltage obtained by the voltage obtaining section and the current obtained by the current obtaining section; and a wire breakage detection section adapted to determine whether or not wire breakage has occurred in the glow plugs on the basis of the result of comparison between the threshold value set for the specific energization state and the combined resistance obtained in the specific energization state for which the used threshold value was set, characterized in that in the case where the energization state determination section determines that the energization state is after-glow energization, the threshold value setting section is adapted to set the threshold value for after-glow energization when the engine is in an idle state, and the resistance obtaining section is adapted to obtain the combined resistance of the glow plugs when the engine is in the idle state. a glow plug connection portion to which the plurality of glow plugs are electrically connected in parallel; a voltage obtaining section adapted to obtain at least one of a voltage supplied from the power supply and a voltage output from the glow plug connection portion; a current obtaining section adapted to obtain a current output from the glow plug connection portion to the glow plugs; an energization state determination section adapted to determine the state of energization of the glow plugs; a threshold value setting section adapted to set a threshold value used for wire breakage determination, wherein the threshold value is set for a specific energization state determined by the energization state determination section; a resistance obtaining section adapted to obtain a combined resistance of the glow plugs connected to the glow plug connection portion on the basis of the voltage obtained by the voltage obtaining section and the current obtained by the current obtaining section; and a wire breakage detection section adapted to determine whether or not wire breakage has occurred in the glow plugs on the basis of the result of comparison between the threshold value set for the specific energization state and the combined resistance obtained in the specific energization state for which the used threshold value was set,