Abstract: A waveform discrimination device includes: a waveform detector receiving waveforms of pulses to be measured and converting the waveforms to electrical signals; an analog amplifier expanding transient waveforms of the electrical signals along a time-domain axis; an AD converter converting the electrical signals to digital data in rise and fall times of the electrical signals; and a signal processing circuit calculating a characteristic-amount of the rise time as a point on a first coordinate axis by using the digital data, and calculating a characteristic-amount of the fall time as a point on a second coordinate axis, so as to define a set of the points on the first and second coordinate axes as a coordinate point, and plot the coordinate point on a discrimination plane, wherein, by plotted positions of the coordinate point, whether the pulses has a first waveform or a second waveform is discriminated.