This was developed as a research and development of platform for the New Energy and Industrial Technology Development Organization (NEDO) funded project of “The Development of a Humanoid Robot Working in an Actual Environment.” The following new features were added to the previous model, the HRP-2 “Promet:” - Dust and splash-proof functions for the joint axes and electric devices, such as the gear box unit and the drive unit. - Multi-finger hands for realisation of more sophisticated hand coordination works. - Improved cooling systems for the heat generated inside the robot body. - Prolonged operation time (120 minutes compared to HRP-2’s 60 minutes). With the successful incorporation of the above functions, it was successfully demonstrated that HRP-3 could be operated at adverse and harsh environments, such as construction sites.