PURPOSE: To maintain the checking to an operator at the frontward and the backward shift turning of an operation handle smoothly by providing a safety mechanism to turn while contacting to a contact unit, and to inform that a gear shift operation shaft is at a high speed gear condition in the shift turning of a handle frame to the front side.

CONSTITUTION: By operating to turn an operation handle facing to the front side, when a gear shift lever 16 is turned downward and a gear shift operation shaft 1 is at the upper level of the sliding, that is, a gear shift transmission mechanism is at a high speed gear condition, a check plate 21 rotating together through a support shaft 12, a supporting member 13, a supporting plate 18, and a bolt 19 is contacted to the starting part of a contact unit 6 with its lower end, and thereby it is rotated against a spring around the bolt 19 as the fulcrum, and rotated together with the operation handle while sliding its lower end to the upper edge of the contact unit 6. And by the sliding resistance at this time, the operator of the operation handle recognizes that the gear shift lever 16 is at a high speed operation condition.