To sustain a high accuracy of print recording at the time of superposed print recording on a single print recording medium using two print recording heads of one line thermal printer.

The number of driving steps of a sheet feed motor 40 is made variable and test print lines L1-L10 are print recorded appropriately on a print recording medium 50 by means of a direct thermal head 14 and a thermal transfer head 16. Print recording state of the test print lines L1-L10 is then discriminated and the number of driving steps of the sheet feed motor 40 is selected when the test print lines L1-L10 by respective heads 14 and 16 coincide with each other. Sheet feed amount of the print recording medium 50 is set for respective heads 14 and 16 by the number of driving steps thus selected.