A pattern drawing apparatus is provided. This apparatus draws a pattern on an object by irradiating the object with an electron beam. A pattern data corresponding to the pattern to be drawn is stored in a memory. The pattern data is sent to a controller that controls irradiation of the electron beam to the object. Check is made whether the controller correctly controls the irradiation of the electron beam in accordance with the stored pattern data. Another memory stores the pattern data per a predetermined number of bits included in the pattern data. The bit data is sent to the controller that generates high and low voltages to control the irradiation of the electron beam. A counter counts the numbers of bits and high or low voltages. A comparator compares the counted numbers of bits and voltages. The comparison results are sent to an indicator that indicates an error when the counted numbers are different from each other. The counted numbers themselves may be indicated. Instead of the comparator, an exclusive-OR circuit may be provided. The bits of the pattern data are exclusive-ORed with the voltages expressed as bits. The output of the exclusive-OR circuit may be indicated as a bit map. Further, the bits of the pattern data and the voltages also may be indicated as bit maps.