To operate a mouse means during the operation of a printer means based on the control of one control means in an input and output device equipped with the mouse means and the printer means.

Print data DATA in one line are serially sequentially transferred to a shift register based on a clock signal CLK, and converted into parallel data, and outputted through a latch circuit to a gate circuit based on a latch signal LATCH, and the logical product of this signal and a strobe signal STB is calculated, and the heating resistor of a thermal head is driven based on the calculated logical product signal. In a time (a) since the start of the transfer of the print data DATA in one line until the output of the latch signal LATCH, a controller is put in charge of the control of a printer, and not able to transmit any mouse information MS generated by a mouse. Then, the transmission of the mouse information MS requiring a communicating time c in a prescribed cycle is performed when the time c is not overlapped with the time (a) so that the operation of the mouse can be performed during the operation of the printer.