To efficiently execute a smoothing treatment and to raise a glossiness.

Three colors of yellow, magenta and cyan are printed in a frame sequential method on a recording paper 11 to obtain a full-color image. After the cyan image is recorded, the smoothing treatment is executed. In the smoothing treatment, smoothing data is generated by using heating data of the cyan image. Each heating element of a thermal head 15 is driven by using the smoothing data. Each heating element of the thermal head 15 is driven by a voltage lower than the applied voltage to the thermal head 15 during the recording of the cyan image so that a cyan thermosensitive coloring layer is not developed in the smoothing treatment. It is possible to efficiently execute the good smoothing treatment whereby a white portion does not turn a yellow color.