A tension transmission device as a control system for a probing portion of a three-dimensional mechanical probe is fitted to a support portion. The tension transmission device includes a driving shaft, a first tension member, and a second tension member. The driving shaft defines first and second fastening points. The first fastening point and the second fastening point are located at axially-distanced points of the driving shaft which are not diametrically opposite. The first and second tension members wind around a circumference of the driving shaft guided by a first pulley and a second pulley, to rotate and manipulate the driven shaft of the probing portion.
