The present invention is a power supply control apparatus that controls pulse discharge occurring in a machining gap in an electric discharge machine. The power supply control apparatus includes: a voltage level detecting device that detects the voltage level of a discharge voltage generated in the machining gap; a voltage level comparator hat compares the voltage level with a voltage level reference value, and outputs a comparison result; and a determining unit that, on the basis of the comparison result, determines whether a discharge pulse is abnormal in a designated one of a plurality of determination modes. The determination method can be designated during machining.