A print head of this invention has a plurality of heater boards, and each heater board has a plurality of heating resistors, driver circuits corresponding to the heating resistors, one shiftregister for inputting serial data, a data latch circuit for latching print data input from the shift register, a pre-heat data latch circuit for latching selection data of selecting one or several of pre-heat signals input from the shift register, and a pre-heat selection circuit for selecting one or a plurality of pre-heat signals in accordance with the selection data latched in the pre-heat data latch circuit. In a print operation, one or several of the plurality of input pre-heat signals are selected to pre-heat the heating resistors, and when a main heat signal is input thereafter, the heating resistors are driven in accordance with the print data latched by the data latch circuit, thus performing the print operation.