In many applications, those who work on assembly processes are required to work in nonergonomic stances. Incorrect positions may cause strain and persistent problems. In addition, strain in workers’ bodies also has a negative effect on labor productivity. Ergonomics should be applied to avoid this kind of negative impact on workers’ health as well as productivity. Ergonomics introduces the basic principles of system productivity and human‐machine‐environment relationship. With a series of computer‐aided ergonomics analysis (CAEA), necessary precautions can be taken in advance by determining the undesirable stances. Through CAEA, productivity for machinery and comfort for people can be ensured by creating an efficient working environment without causing health problems for workers who work in production. In this study, in an agricultural equipment producing company, current working positions of a worker carrying out tasks during the assembly of wheel hay rakes, have been evaluated via the CATIA Ergonomic Analysis Module. On the basis of the results, the design of the assembly unit was ergonomically improved. As a result of the improvement in the working environment, unfavorable stance positions were avoided and production time was decreased by 60%.