To compactly mount a detector, by easily mounting from the outside a switch for detecting the neutral position and reverse position, and effectively utilizing space in the rod axial center direction end part of a shift rod.

This speed change position detector for a vehicle running on an off road is provided with a gear type transmission for switching a speed change position, by moving a shift rod 72 operated in the rod axial center direction so as to move a shift sleeve 70. A position detection switch 95, 99, detecting a neutral position and a reverse position of the shift rod 72 by movement of its rod axial center direction, is arranged in a part of a speed change case 11 in the rod axial center direction one end side of the shift rod 72. Preferably, forward two stages, neutral, and reverse are set freely switchable by a single shift rod 72, the reverse position detection switch 99 is arranged facing in the rod axial center direction end face, and the neutral position detection switch 95 is arranged outward in the radial direction with respect to the shift rod 72.