PURPOSE: To measure the climbing-over force of the synchro hub sleeve accurately in a short time by detecting the climbing-over force by a driving force detecting device such as a load cell, and reading it directly on an electric display device.

CONSTITUTION: When a driving cylinder 29 is put in operation to move force its piston rod 30 as shown by an arrow A, a driving rod 26 moves forth in the same direction through a floating connector 31 and the load cell 5, a fork 21 moves as shown by an arrow A, and a sink head 35 climbs over the edge part 28e of a synchro sleeve 28 from its center groove 28b to enter a right-side groove 28c, so that the current climbing-over force operates on the load cell 5 as compressive force and is detected. The result is inputted to the display device 6 and is displayed on the display part 33, and one of lamps N-NG, OK, and H-NG illuminates, so that the result of a conforming/nonconforming judgement is displayed.