Study on improvement of job-order oriented production by Toyota's Production Management Theory, that is, Toyota's Production Smoothing can be achieved on job-order oriented produciton by MPR(Material Requirement Planning) sysetm which is applied as a method of making continuous material flow, instead of a production management system as usually applied in Japanese companies.At the same time, productivity of job-order oriented production may be improved by application of the Toyota's consideraiton in production methods.