1. A method for creating a paint color database, comprising: a first step of storing spectral reflectance data of a plurality of paint colors in a recording unit after associating each spectral reflectance data with a code for specifying each paint color; a second step of storing color category evaluation values of sample paint colors selected from the plurality of paint colors in the recording unit after associating the each color category evaluation value with the code; a third step of calculating characteristic quantities of the paint colors expressing color categories using the spectral reflectance data, and storing the characteristic quantities in the recording unit after associating the each characteristic quantity with the code; a fourth step of carrying out a process for training a neural network having input units corresponding to the characteristic quantities and output units corresponding to the color category evaluation values, using the characteristic quantities and the color category evaluation values of the sample paint colors as training data; and a fifth step of inputting characteristic quantities of the paint colors other than the sample paint colors into the neural network after the training process, and storing output data in the recording unit after associating the each output data with the code.