A thermal color printer has a rotatable platen drum, clamp claws provided on the platen drum for clamping a tip end of a sheet of paper which is wrapped around an outer peripheral surface of the platen drum, a thermal printing head having a release position separated from the outer peripheral surface of the platen drum and a print position for printing an image on the paper, a mechanism for feeding an ink sheet between the thermal printing head and the paper on the platen drum, where the ink sheet has portions of n different colors so that a printing in n different colors completes while the platen drum undergoes n revolutions, and a paper pushing mechanism including at least a sliding member which has an active position for holding down the paper on the platen drum by making sliding contact with the paper while the platen drum rotates and an inactive position which is separated from the outer peripheral surface of the platen drum.