To easily handle a jig for adjusting tappet clearance by even a beginner with low skillfulness and to smoothly and exactly perform an adjusting work.

A ratchet type torque control mechanism T is constituted by arranging a plurality of steel balls 12 at an intermediate flange part 4f of an outer wrench main body 4 having a fitting part 4k fittable into an adjust nut N, engaging the steel balls 12 to a plurality of radiating grooves 10m of a ring member 10 of a rotation operating body 5 and pressing the balls 12 by a spring 6. An inner wrench 3 is inserted into an insertion hole h of the outer wrench main body 4 and an adjust bolt B can be adjusted by a driver 3a at a tip.