Provided is controlling apparatus for an electric motor which is driven in accordance with a driving signal input through electric contacts held in slide contact with each other, the controlling apparatus including: a superimposed signal generating unit, which generates a superimposed signal having a peak voltage higher than a voltage of the driving signal; and a controlling unit, which generates the driving signal based on a controlling signal input so as to control the driving of the electric motor, and superimposes the superimposed signal onto the driving signal and output the resultant signal to the electric motor, the controlling unit superimposing the superimposed signal onto the driving signal and outputting the resultant signal to the electric motor when a state in which the driving signal is lower than a predetermined voltage continues for a time period which is longer than a predetermined time period.