there is provided an apparatus for measuring a position of a linear type valve which is open / shut by operation of a hydraulic cylinder . more particularly , the apparatus more accurately measures a valve position by outputting a rotation angle of a rotation sleeve which rotates by being operatively connected to a hydraulic cylinder which moves linearly , and by calculating a vertical movement distance of a valve gate which changes in proportion to the rotation angle . further , since the structure of the apparatus is very simple , the cost of production is significantly reduced . in addition , for use , the apparatus is installed on the hydraulic cylinder by a simple method .