1. Disease determination method for determining whether a person has a certain disease or not using a biological sample, comprising; pretreatment process to add an acidic or alkaline solution to the sample and to heat the sample, excitation light irradiation process to irradiate the sample with excitation light and to continuously or intermittently change the wavelength of the excitation light, emission light measurement process to measure the wavelength and intensity of the emission light emitted from the sample in response to the excitation light, analyzing and sorting process to detect a specific point in the three-dimensional optical spectrum composed of the excitation light wavelength, emission light wavelength and emission light intensity and to sort or hierarchize the sample based on the specific point attribute, and determination process to determine the presence or absence of the disease or the condition of the disease of the body to which the sample belongs based on the sorting and hierarchization results of the sample.