For electron beam drilling, a high power density beam must be used. However, decision of distribution of high power density electron beam is very difficult, because such a beam can easily drill a metal target. In the present paper, a method for deciding the distribution of power density is discussed. Namely, the distribution of temperature rise is calculated by assuming that the power density obeys the normal distribution, of which standard deviation is different with respect to x-axis and y-axis respectively and that transforming the conduction of heat to the two dimensional problem by using a thin aluminum foil, of which thickness is smaller than the range of electron penetration. Moreover, the foil is drilled by pulsed beam. From the experimental dimensions of hole, the pulse duration and the calculated temperature rise, the distribution of power density is estimated.