The present invention includes an antenna for measuring an electromagnetic wave radiated from a device to be measured stemming from partial discharge and having sensitivity at least in the UHF band; a filter for extracting a TEM mode component from a measured time waveform; and a measurement device body including a processing section adapted to obtain a second order integral value of the time waveform having undergone the filter processing and obtain a discharge charge quantity from the value. The present invention also comprises an electromagnetic wave radiation simulating apparatus for inputting a pseudo discharge signal to the device to be measured and previously obtaining the relation between the second order integral value and the discharge charge quantity, the processing section obtains the discharge charge quantity from the second order integral value with reference to the previously obtained relation between the second order integral value and the discharge charge quantity.