To control capstan marks appearing on a recording medium due to a capstan roller while assuring the transportation power of the recording medium by the capstan roller.

In a thermal printer 10 which performs printing by heating each heating element 11a of a thermal head 11 while pinching a print sheet 20 between a capstan roller 21 and a pinch roller 22 and carrying the print sheet 20 through rotation of the capstan roller 21 coming into pressure contact with the print sheet 20, the capstan roller 21 is provided with a plurality of protrusions 21a on the surface coming into pressure contact with the print sheet 20, and a pinch pressure varying device 40 for adjusting the pressure contact force between the capstan roller 21 and the print sheet 20 adjusts the pressure contact force when the thermal head 11 is printing on the print sheet 20 to become smaller than that when printing is not performed.