1. A signature recognition apparatus comprising: input means for reading a handwritten signature and outputting handwriting data corresponding to the read handwritten signature; characteristic extraction means for extracting characteristics from the handwriting data outputted from the input means and outputting characteristic handwriting data in accordance with the extracted characteristic elements; sample generating means for receiving the characteristic handwriting data and generating a plurality of truth sample data corresponding to a qualified person's true handwritten signature and a plurality of falsehood sample data corresponding to other than the qualified person's true handwritten signature, each of said truth sample data and said falsehood sample data being the mathematical product of the received characteristic handwriting data multiplied by each of a plurality of different specified coefficients; learning control means for outputting a teacher signal representative of whether the characteristic hand-writing data is a qualified-person's true one; and neural net means for receiving the sample data plurally generated from the sample generating means, learning a more suitable coupling load coefficient by comparing the sample data and the teacher signal, and according to the coupling load coefficient determined through a learning operation, judging whether or not newly inputted characteristic handwriting data of a handwritten signature is the qualified-person's true handwritten signature.