PURPOSE: To optically fix a plurality of thermal color forming layers at the same time by providing first and second specific passages and a U-shaped ultraviolet lamp.

CONSTITUTION: Color thermal recording paper 11 having at least first - third thermal color forming layers different in thermal sensitivity and developing different colors formed thereon is used and the respective thermal color forming layers are thermally recorded from above in succession by a thermal head 21. The first thermal color forming layer being the uppermost layer is irradiated with ultraviolet rays of a first wavelength region to be optically fixed and the second thermal color forming layer is irradiated with ultraviolet rays of a second wavelength region. In this thermal color printer, the first passage 28 into which the recording paper 11 introduced during the recording of the first thermal color forming layer and the second passage 27 into which the recording paper 11 is introduced during the recording of the second thermal color forming layer are provided. Further, a U-shaped ultraviolet lamp 32 wherein first and second straight pipe parts 32a, 32b coated with phosphors emitting ultraviolet rays of first and second wavelength regions are respectively arranged in the first and second passages 28, 27 is provided.