A problem to be solved is to use a measured pain degree for comparison with a pain degree of another subject or for diagnosis of a disease. A pain measuring device has an electrode to be attached to a subject and a stimulation current generation means generating a stimulation current to be supplied to the electrode. Then, the pain measuring device measures pain felt by the subject based on the stimulation current applied from the electrode to the subject. The pain measuring device has a means to display a relation between a pain measurement value being a logarithmic value or a logarithmic-type value of a value founded on the stimulation current and a value of a VAS or a face scale which the subject selects.