This paper gives an experiment of redesign by the joint approach of both job enlargement and simplification in the conveyer line of a firm. We applied the Herzberg's Motivation-Hygiene theory, the contingency theory of behavioral science and the socio-technical systems approach. Motivation seekers adapt to an enlarged job. Hygiene seekers adapt to a simplified job. As a result, the productivity increased and job satisfaction improved. The problem between Industrial Engineering and Behavioral science is not only presenting whether or not to enlarge or to simplify a job, but also to consider the joint approach of both job enlargement and simplification.