PURPOSE: To realize good lubrication of a speed meter gear by providing a gear for lubricating the speed meter gear in the vicinity of the speed meter gear and providing a counter shaft gear which meshes with the gear for lubrication in such a manner that the relative rotation is possible.

CONSTITUTION: When a transmission is shifted by any gear when a vehicle starts and a main shaft 3 starts to rotate, a gear for lubricating a speed meter gear 10 rotates, and a counter shaft gear 12 which meshes with the gear 10 is rotated by following it up. Lubricating oil on the bottom of a transmission case is scraped up by the gear 12 and supplied to the gear for lubrication 10. Since the gear for lubrication 10 is a helical gear, it splashes lubricating oil backward as it rotates. In addition, since the gear for lubrication 10 has approximately the same diameter as or slightly smaller diameter than that of a rear bearing 4, lubricating oil which is splashed backward flows backward through a clearance between rollers of the rear bearing 4 to lubricate a mesh section of a speed meter gear 6 and a worm wheel 7.