There are provided a printing apparatus and a method of making a mask pattern for exposure by the use of the printing apparatus. A temperature of a thermal head is detected, and a plurality of split pulses formed by dividing a strobe pulse applied to the thermal head are sequentially applied with quiescent periods interposed therebetween. There is stored in advance pulse-applying data of settings of a cumulative period of pulse-applying periods over which the plurality of split pulses are respectively applied, a number of the split pulses, the split pulse-applying periods, and the quiescent periods, defined in a manner corresponding to values of the temperature of the thermal head. Appropriate pulse-applying data is read out according to the temperature detected, and application of the split pulses is controlled according to the appropriate pulse-applying data. In another form, the split pulses are controlled in a manner such that the cumulative period of the split pulse-applying periods is sufficient for a time period over which the strobe pulse is required to be applied.