An electrical discharge machine (10, 10A, 10B) configured to perform electrical discharge machining by applying a voltage to an inter-electrode gap formed between an electrode and a target workpiece and causing a current to flow, the electrical discharge machine (10, 10A, 10B) comprising: a machining power supply (12, 12A, 12B) having a plurality of different circuit states, and configured to be capable of being set to one circuit state of the plurality of circuit states by switching at least one of an electrical connection and an electrical setting; and a numerical control device including a control unit, the control unit being characterized by comprising: a setting switching unit configured to set each of the plurality of circuit states as the circuit state of the machining power supply (12, 12A, 12B) sequentially by switching at least one of the electrical connection and the electrical setting, a state determining unit configured to, when each of the plurality of circuit states is set as the circuit state of the machining power supply (12, 12A, 12B) by the setting switching unit, determine whether or not the set circuit state is normal; and a failure portion specifying unit configured to specify a failure portion of the machining power supply (12, 12A, 12B), the failure portion being a component such as a resistor (R1, R2), a pulse input circuit (A, B), a capacitor or a diode, based on a normality/abnormality determination result with respect to each of the plurality of circuit states provided by the state determining unit; wherein the numerical control device further comprises a table configured to store beforehand for each failure portion an abnormality pattern of the plurality of circuit states associated with the failure portion, the abnormality pattern being information as to, in case of failure of the failure portion, whether each of the plurality of circuit states is normal or abnormal, wherein the failure portion specifying unit is configured to specify the failure portion by comparing the abnormality patterns stored in the table and the normality/abnormality determination result with respect to each of the plurality of circuit states provided by the state determining unit, wherein the numerical control device further includes a reporting unit configured to report the failure portion specified by the failure portion specifying unit to an operator. a machining power supply (12, 12A, 12B) having a plurality of different circuit states, and configured to be capable of being set to one circuit state of the plurality of circuit states by switching at least one of an electrical connection and an electrical setting; and a numerical control device including a control unit, the control unit being characterized by comprising: a setting switching unit configured to set each of the plurality of circuit states as the circuit state of the machining power supply (12, 12A, 12B) sequentially by switching at least one of the electrical connection and the electrical setting, a state determining unit configured to, when each of the plurality of circuit states is set as the circuit state of the machining power supply (12, 12A, 12B) by the setting switching unit, determine whether or not the set circuit state is normal; and a failure portion specifying unit configured to specify a failure portion of the machining power supply (12, 12A, 12B), the failure portion being a component such as a resistor (R1, R2), a pulse input circuit (A, B), a capacitor or a diode, based on a normality/abnormality determination result with respect to each of the plurality of circuit states provided by the state determining unit; a setting switching unit configured to set each of the plurality of circuit states as the circuit state of the machining power supply (12, 12A, 12B) sequentially by switching at least one of the electrical connection and the electrical setting, a state determining unit configured to, when each of the plurality of circuit states is set as the circuit state of the machining power supply (12, 12A, 12B) by the setting switching unit, determine whether or not the set circuit state is normal; and a failure portion specifying unit configured to specify a failure portion of the machining power supply (12, 12A, 12B), the failure portion being a component such as a resistor (R1, R2), a pulse input circuit (A, B), a capacitor or a diode, based on a normality/abnormality determination result with respect to each of the plurality of circuit states provided by the state determining unit; wherein the numerical control device further comprises a table configured to store beforehand for each failure portion an abnormality pattern of the plurality of circuit states associated with the failure portion, the abnormality pattern being information as to, in case of failure of the failure portion, whether each of the plurality of circuit states is normal or abnormal, wherein the failure portion specifying unit is configured to specify the failure portion by comparing the abnormality patterns stored in the table and the normality/abnormality determination result with respect to each of the plurality of circuit states provided by the state determining unit, wherein the numerical control device further includes a reporting unit configured to report the failure portion specified by the failure portion specifying unit to an operator.