A vehicle transmission having a pair of left and right HSTs for driving respective axles is applicable for a riding lawn mower. The transmission comprises a center casing incorporating a distributing drive train. In the fore-and-aft direction, an input shaft of the distributing drive train projects from the center casing toward a prime mover, and a PTO shaft for driving a mower unit projects from the center casing opposite to the prime mover. A pair of left and right deceleration drive train casings for incorporating respective deceleration gear trains and supporting the respective axles are disposed on respective left and right sides of the center casing. A pair of left and right stepless transmission mechanisms, each of which is drivingly interposed between the distributing drive train and each of the deceleration gear trains in the deceleration gear train casings, are mounted on left and right side portions of the center casing opposite to the prime mover in the fore-and-aft direction.