PURPOSE: To obtain a mower, constituted so as to enable cleaning of weeds while reciprocating a cutting blade along a hillside by rotation and regulation of a transmission case simultaneously with mowing on horizontal land and capable of efficiently carrying out mowing work of the respective horizontal land and hillside.

CONSTITUTION: A transmission case 7 is fixed in a state to provide a cutting blade 10 in a horizontal posture and the cutting blade 10 is reciprocated and rocked by a driving mechanism 24 to carry out mowing work on a horizontal land. The transmission case 7 can be rotated and regulated until the cutting blade 10 attains a posture along a hillside to be mowed and then fixed. Mowing work of a hillside can be carried out by reciprocating and rocking the cutting blade 10. Since the power of the PTO shaft 9 is distributed and transmitted to a pair of driven shafts 14 and 15 on both sides, a transmission structure is reasonably arranged in good balance.