A ride-on lawn mower includes a traveling vehicle body including an operators seat (50), and a wheel post (53) for supporting a steering wheel (52) mounted forward of the operators seat. The lawn mower further includes a mower apparatus (20) connected to a front part of the traveling vehicle body, a roll-over protective structure (56) mounted in a rear part of the operators seat, and a front guard (57) extending upward from the wheel post (53) and forward of the steering wheel (52).