To provide a waveform determining apparatus which can provide an accurate and quick understanding of factors for a faulty waveform, with respect to an input signal.

The waveform decision apparatus comprises a measurement section for measuring the input signal at a predetermined cycle to output a measured value and a decision section for performing a pass/fail decision on the input signal, on the basis of signal waveforms WS1 to WS4 on the basis of the measured value and an allowable area F for the signal waveforms WS1 to WS4. The decision section specifies a position decision area, to which a part or the whole of a section of the signal waveforms WS1 to WS4 being outside the allowable area F belongs, from among position decision areas Z1 to Z5, set outside the allowable area F and makes at least either the information on the specified position decision area or the information associated with the specified position decision area stored to a storage section.