An offset rotary joint unit equipped with a rotation correction mechanism, in which a bending motion can be executed in a two-dimensional plane only by virtue of a rotary mechanism and which can support a high-load weight and is applicable for two-arm mechanisms such as nursing assistant robots. One offset rotary joint unit 4 is composed of a first arm 1, a rotation correction arm 2 rotationally driven around the axial line of the first arm, and a second arm 3 rotationally driven around an axial line obliquely intersecting with the rotation correction arm. A rotation correction joint mechanism 5 linking the first arm 1 and the rotation correction arm 2 and an offset rotary joint mechanism 6 linking the rotation correction arm 2 and the second arm 3 are driven by a single motor 12, and the rotation correction joint mechanism 5 rotates synchronously and in the reverse direction, following the rotation of the offset rotary joint mechanism 6, thereby allowing the second arm 3 to execute a bending motion in a two-dimensional plane with respect to the first arm 1 only by virtue of rotary mechanisms.