A tractor frame comprises a pair of left and right cranked side frame elements
disposed in parallel. Each of the cranked side frame elements includes a web portion
at a longitudinally intermediate portion of the cranked side frame elements, a
front level portion extended forward from the web portion, and a rear level portion
extended backward from the web portion so that a top of the rear level portion
is lower than a top of the front level portion. A footboard is provided on the
top of the rear level portion.