The present invention provides a wrist mechanism with three degrees of freedom for an industrial robot, which is compactly formed and to which a tool is mounted. The first degree of freedom is associated with a first input shaft for rotating a wrist portion at a low speed. The second and third degrees of freedom are associated with rotating the tool or tilting the wrist. In order to attain these motions, second and third input shafts concentrically arranged relative to the first input shaft are used for transmitting motion to, through bevel gears, speed reduction mechanisms each symmetrically disposed at right and left sides, and the outputs therefrom are used to drive the tool and wrist.