A structure for mounting a mountable/dismountable component (16) on a machine body (11) of a working machine (10) including: locking sections (38a, 62) provided on the machine body for locking the mountable/dismountable component； and engagement sections (71, 75) provided on the mountable/ dismountable component and engageable by respective ones of the locking sections (38a, 62). The locking sections include: a movable locking section (62) capable of sliding the mountable/dismountable component to a predetermined mounting position on the machine body while locking the first engagement section (71) of the engagement sections； and a fixed locking section (38a) constructed to lock a second engagement section (75), different from the first engagement section, of the engagement sections of the mountable/dismountable component in the predetermined mounting position.
