Abstract: A three-dimensional shape descriptor extractor is implemented by collecting surface data from a three-dimensional shape as learning data and training a set of a prescribed encoder and a prescribed decoder by using the learning data, wherein the training extracts a three-dimensional shape descriptor from the learning data by using the encoder, undoes the three-dimensional shape descriptor by using the decoder, evaluates a difference between a state before using the encoding and a state after using the decoding, and adjusts the encoder and the decoder so as to reduce the difference, and mesh data is collected from the three-dimensional shape as the surface data and made to have a prescribed scale, so as to train the encoder and the decoder.