A single axis actuator includes a driving-side timing pulley located at one end in a longitudinal direction of a device frame in such a manner that a rotational center thereof is vertically oriented, a rotation transmission shaft coaxially connected to the driving-side timing pulley and extending upwardly, a driven-side timing pulley located at another end in the longitudinal direction of the device frame in such a manner that a rotation shaft thereof is vertically oriented, a timing belt bridged between the driving-side and driven-side timing pulleys, a slider connected to a part of the timing belt to be made movable in the longitudinal direction of the device frame, and a motor having a motor shaft that is connected to an upper end of the rotation transmission shaft.