A thermal printer, comprising: a thermal head; a platen roller disposed to face said thermal head; a first path that guides recording paper drawn from a recording paper roll to one entrance of a gap between said thermal head and said platen roller such that a first main surface of said recording paper is on said thermal head side; a second path that guides said recording paper drawn from said recording paper roll to the other entrance of the gap between said thermal head and said platen roller such that a second main surface of said recording paper is on said thermal head side; and a switch guide that switches between said first path and said second path; wherein the thermal printer is configured to perform a first print operation mode of switching said switch guide to said first path and guiding said recording paper into said first path to perform printing on said first main surface of said recording paper; next, a rewind operation mode of rewinding said recording paper on which printing has been performed by said first print operation mode; and then a second print operation mode of switching said switch guide to said second path after said recording paper has been rewound by said rewind operation mode and guiding said recording paper into said second path to perform printing on said second main surface of said recording paper; wherein said thermal printer is further configured to perform printing on both said first and second main surfaces of said recording paper being connected to said recording paper roll; wherein said first main surface of said recording paper is an inner surface of said recording paper roll, wherein said second main surface of said recording paper is an outer surface of said recording paper roll, wherein the thermal printer further comprises a housing path that houses said recording paper on which printing has been performed by said first print operation mode, and wherein said housing path is curved in the same direction as a winding direction of said recording paper roll. a thermal head; a platen roller disposed to face said thermal head; a first path that guides recording paper drawn from a recording paper roll to one entrance of a gap between said thermal head and said platen roller such that a first main surface of said recording paper is on said thermal head side; a second path that guides said recording paper drawn from said recording paper roll to the other entrance of the gap between said thermal head and said platen roller such that a second main surface of said recording paper is on said thermal head side; and a switch guide that switches between said first path and said second path; wherein the thermal printer is configured to perform a first print operation mode of switching said switch guide to said first path and guiding said recording paper into said first path to perform printing on said first main surface of said recording paper; next, a rewind operation mode of rewinding said recording paper on which printing has been performed by said first print operation mode; and then a second print operation mode of switching said switch guide to said second path after said recording paper has been rewound by said rewind operation mode and guiding said recording paper into said second path to perform printing on said second main surface of said recording paper; wherein said thermal printer is further configured to perform printing on both said first and second main surfaces of said recording paper being connected to said recording paper roll; wherein said first main surface of said recording paper is an inner surface of said recording paper roll, wherein said second main surface of said recording paper is an outer surface of said recording paper roll, wherein the thermal printer further comprises a housing path that houses said recording paper on which printing has been performed by said first print operation mode, and wherein said housing path is curved in the same direction as a winding direction of said recording paper roll.