A harvester 1 in which a machine body frame 30 is secured on a crawler-type travel apparatus 10 and an engine 50 is mounted in the longitudinal central portion of the machine body frame 30, so that it is possible to dispose a muffler in an open space in an engine room that is unlikely to be exposed to dust, wherein a stepped section 21a that is recessed toward the interior of the engine room 21 is formed on one side laterally of the engine room 21, which contains the engine 50, a muffler 70 is mounted and secured in the stepped section 21a, and the muffler 70 is covered by a muffler cover 71, the muffler cover 71 being disposed so as to cover the top and/or the side of the stepped section 21a.
