Since Japan has become a society with a decreasing birthrate and also with aged people recently, it will be difficult for the Japanese shipbuilding industry to prosper as former glorious days, unless the industry makes effort to restructure the manufacture system as suitable for the human oriented production. In such circumstance, to increase productivity and to keep safety and health of the workers are the most important for the companies. Using biomechanics and ergonomics, together with computer simulation techniques, it will be possible to establish the virtual ergofactory which concords productivity with humanity well. This report has picked up the physical works in shipbuilding such as lifting, carrying, pushing, and pulling and the human task simulation by using general purpose program “Jack” has been carried out; the static strength prediction on human body, low back compression analysis, and also metabolic energy expenditure analysis. As the result, it can be proposed theoretically that the lifting, pushing and pulling loads should be limited under 30kg, and the carrying load should be limited under 40kg, so as to keep the local torque and/or forces on segments and joints in a human body under the allowable values of them.