To provide a front wheel unit for a mower, designed to make a changeover of the fixing/turning of caster-type front wheels with or without interlocking with another operation.

This mower has such a construction that a machine body composed of a reaping unit subject to rotary driving by an engine, driving wheels 17R and 17L disposed behind the reaping unit and front wheels disposed in front of the reaping unit is mounted with a steering handle 30 so as to be turnable transversely or vertically or fixable. The steering handle 30 is mounted with turning control levers 4R and 4L for making a changeover operation for the left and right driving wheels 17R and 17L between a driven mode and a non-driven mode, and the turning control levers 4R and 4L and a locking mechanism for checking the left and right turning motions of the front wheels are interlockingly joined to each other.