A control device for a reducing agent supply apparatus for controlling the reducing agent supply apparatus having reducing agent collecting means for collecting a reducing agent inside reducing agent supply paths in an exhaust gas purification apparatus that adds the reducing agent to an exhaust gas upstream side of a reducing catalyst disposed inside an exhaust gas passageway of an internal combustion engine, and reduces and purifies nitrogen oxides contained in exhaust gas using the reducing catalyst, includes: a stop detection portion that detects when the internal combustion engine stops; a reducing agent collecting means control portion that starts collection of the reducing agent inside the reducing agent supply paths when the internal combustion engine stops; and an injection valve control portion that keeps a reducing agent injection valve closed when the reducing agent collecting means starts operating and opens the reducing agent injection valve after a predetermined time period elapses.