PURPOSE:To decrease a steel leakage accident and to control a sliding valve device always in a normal condition by mounting bar type torque meter mounting parts to one end of tightening arms of a toggle mechanism and measuring the face pressure acting on the actual sliding surface. CONSTITUTION:Links 13 are freely rotatably engaged with both ends of spring 7 holders 8 engaging with a housing 2 and tightening arms 14 are freely rotatably pinned 15 to the other end of the links 13. The surface pressure of the sliding surface 10 can be checked as springs 7 generate deflections when the other ends of the arms 14 are engaged with pins 16 fixed to clamps 6 and the bar type torque meters 17 are inserted to the arms 14 and are rotated in the direction of an arrow 18. The surface pressure is obtd. by converting the max. tightening torque value when the arms 14 are rotated by the meters 17 to the surface pressure. The surface pressure of each time is known at the time of setting bricks to the slide valve device by such constitution and therefore, the steel leakage accident, etc. are decreased and the safe operation is executed.