A thermal printer allows ink ribbon replacement without interference of a hook positioned in the opened state particularly in an ink ribbon replacement operation.A thermal printer includes a head lock lever 40 which includes a hook 41 at the tip of the lever. The hook is mounted such that it can be moved in the longitudinal direction relative to a turn shaft 26 during turning of the turn shaft 26, allowing the distance between the turn shaft 26 and the hook 41 to be changed. A movement control moves the head lock lever 40 such that the distance between the turn shaft 26 and the hook 41 in the opened state in which the thermal head 12 is separated from the platen roller 11 is smaller than that in the pressed state in which the thermal head 12 is pressed into contact with the platen roller 11.