Abstract
The purpose of this study is to revise the decision rule for working posture of upper limb in the digital human model focusing to the work involving forearm torsion such as screw driving. In the previous report the decision rule was decided as the upper limb took the posture so as to maximize the degree of coincidence of direction vectors. However the error of around 10% of maximum degree of coincidence existed depending on the hand position. In this report revised rule was studied.