PURPOSE: To raise the quality of recorded images with constant density by preheating a heating resistor at a temperature at which no printing takes place during the period when the recording operation of a heat-sensitive recording head is stopped.

CONSTITUTION: One ends of lead wires 2 and 3 are alternately connected to one small and long heating resistor 1 provided on the base plate of a heat-sensitive recording head and the other ends are connected through diodes 4 preventing reverse current to source drive wires 5 and 6. To the middle point of the connection points of the lead wires 2 and 3, one ends of lead wires 8 bitted at the output ends of a shift register 7 are connected. The input terminal of the shift register 7 is connected with a data signal line 13 whose one end is connectd with the output side of a data selector 12 which selects image data 14, heat storage data 15, or white data 16. For example, when intervals are present between image signals, heat storage data 15 are chosen.