To simplify a structure requiring no arrangement of a pulley and a belt in a link while realizing the same motion as that of the conventional robot and to enhance reliability and an action speed by requiring no arrangement of a motor at a connection part of two links.

Base end sides of the links 3 and 4 are coaxially and rotatably connected to a base part 2 and the links 5 and 6 are rotatably connected to tip end sides of the links 3 and 4, respectively. The tip end sides of the links 5 and 6 are rotatably connected to each other to constitute the links 3, 4, 5 and 6 to a quadrilateral shape. An end effecter 7 is rotatably connected to the tip end side of the link 6 by the motor 8. By separately rotating/driving the links 3 and 4 respectively, the links 5 and 6 are moved while varying the quadrilateral shape and an axis position of the end effecter 7 is moved.