An amount of electric power consumption by a battery is reduced, and deterioration of a coil is suppressed by efficiently heating an injector and melting urea crystals at an early stage.A control device for a reducing agent injection device fills the device with a reducing agent at a start-up of an internal combustion engine and executes control for injecting the reducing agent into an exhaust passage of the internal combustion engine by the injector. The control device includes an energization control section that executes energization control in which, after an exhaust temperature of the internal combustion engine becomes equal to or higher than a specified threshold value, a temperature of the injector is increased by energizing the coil of the injector for a specified time and melting of the crystals of the reducing agent precipitated in the injector is promoted.