A wire electric discharge machine configured to apply a pulse voltage to a machining gap between a wire electrode and a workpiece so that the workpiece is machined by electric discharge, the wire electric discharge machine comprising: a power supply device for electric discharge machining comprising a plurality of DC power supply devices (VM1-VM5), supply voltage switching means (SW1-SW5, 32) for changing the plurality of DC power supply devices, and current supply means (SW6, SW7, 32) for turning on and off the supply of a discharge current to the machining gap from the DC power supply device changed by the supply voltage switching means; memory configured to store received data on the type of the workpiece material; the wire electric discharge machine being characterized in that it further comprises: a controller configured to control the supply voltage switching means and the current supply means of the power supply device for electric discharge machining, adjust the magnitude and the pulse of a pulse voltage applied to the machining gap, and adjust a peak current value of a total discharge current flowing to the wire electrode and the current pulse width within ranges of 30 to 150 amperes and 0.3 to 6.4 microseconds, the wire electric discharge machine being configured, when the material of the workpiece is graphite or a carbon composite, to give a command from the controller to the supply voltage switching means, adjust the pulse voltage applied to the machining gap and the pulse width of the pulse voltage, give a command from the controller to the current supply means, set the peak current value of the total discharge current flowing to the wire electrode and the current pulse width so as to be suitable for machining of the graphite or carbon composite material, and perform the machining with a gentle rise of a machining current, the peak current value reduced, and the current pulse width increased. a power supply device for electric discharge machining comprising a plurality of DC power supply devices (VM1-VM5), supply voltage switching means (SW1-SW5, 32) for changing the plurality of DC power supply devices, and current supply means (SW6, SW7, 32) for turning on and off the supply of a discharge current to the machining gap from the DC power supply device changed by the supply voltage switching means; memory configured to store received data on the type of the workpiece material; the wire electric discharge machine being characterized in that it further comprises: a controller configured to control the supply voltage switching means and the current supply means of the power supply device for electric discharge machining, adjust the magnitude and the pulse of a pulse voltage applied to the machining gap, and adjust a peak current value of a total discharge current flowing to the wire electrode and the current pulse width within ranges of 30 to 150 amperes and 0.3 to 6.4 microseconds, the wire electric discharge machine being configured, when the material of the workpiece is graphite or a carbon composite, to give a command from the controller to the supply voltage switching means, adjust the pulse voltage applied to the machining gap and the pulse width of the pulse voltage, give a command from the controller to the current supply means, set the peak current value of the total discharge current flowing to the wire electrode and the current pulse width so as to be suitable for machining of the graphite or carbon composite material, and perform the machining with a gentle rise of a machining current, the peak current value reduced, and the current pulse width increased. a controller configured to control the supply voltage switching means and the current supply means of the power supply device for electric discharge machining, adjust the magnitude and the pulse of a pulse voltage applied to the machining gap, and adjust a peak current value of a total discharge current flowing to the wire electrode and the current pulse width within ranges of 30 to 150 amperes and 0.3 to 6.4 microseconds, the wire electric discharge machine being configured, when the material of the workpiece is graphite or a carbon composite, to give a command from the controller to the supply voltage switching means, adjust the pulse voltage applied to the machining gap and the pulse width of the pulse voltage, give a command from the controller to the current supply means, set the peak current value of the total discharge current flowing to the wire electrode and the current pulse width so as to be suitable for machining of the graphite or carbon composite material, and perform the machining with a gentle rise of a machining current, the peak current value reduced, and the current pulse width increased.