A vehicle including a vehicle body (10, 310) and a front wheel that is disposed anterior to the vehicle body (10, 310) and that is steerable about a steering axis (Cs), the vehicle body (10, 310) including a vehicle body frame and a steering rotation unit (13, 313) that is supported on the vehicle body frame and that rotates about the steering axis (Cs), the vehicle characterized by comprising: a variable trail length mechanism (30, 330) that varies a trail length (t) of the front wheel, the variable trail length mechanism (30, 330) including: an oscillation unit (41, 41) that is connected with the steering rotation unit (13, 313) so as to be oscillatable in a fore-aft direction and that supports the front wheel; and a torsion reduction portion that reduces torsion of the oscillation unit (41, 341) in a vehicle width direction through the oscillation unit (41, 341) combined with the steering rotation unit (13, 313) under a condition in which the trail length (t) is changed such that the front wheel is disposed at a rearmost position, wherein the torsion reduction portion includes a fitted portion (90, 390) disposed in the steering rotation unit (13, 313) and a fitting portion (100, 300) that is disposed in the oscillation unit (41, 341) and that can be fitted in the fitted portion (90, 390), the fitting portion (100, 300) fits in the fitted portion (90, 390) under a condition in which the trail length (t) is changed such that the front wheel is disposed at the rearmost position, characterised in that the fitting portion is a protrusion protruding to a rear, and the fitted portion is a recess in which the protrusion fits.. a variable trail length mechanism (30, 330) that varies a trail length (t) of the front wheel, the variable trail length mechanism (30, 330) including: an oscillation unit (41, 41) that is connected with the steering rotation unit (13, 313) so as to be oscillatable in a fore-aft direction and that supports the front wheel; and a torsion reduction portion that reduces torsion of the oscillation unit (41, 341) in a vehicle width direction through the oscillation unit (41, 341) combined with the steering rotation unit (13, 313) under a condition in which the trail length (t) is changed such that the front wheel is disposed at a rearmost position, wherein the torsion reduction portion includes a fitted portion (90, 390) disposed in the steering rotation unit (13, 313) and a fitting portion (100, 300) that is disposed in the oscillation unit (41, 341) and that can be fitted in the fitted portion (90, 390), the fitting portion (100, 300) fits in the fitted portion (90, 390) under a condition in which the trail length (t) is changed such that the front wheel is disposed at the rearmost position, characterised in that the fitting portion is a protrusion protruding to a rear, and the fitted portion is a recess in which the protrusion fits.. an oscillation unit (41, 41) that is connected with the steering rotation unit (13, 313) so as to be oscillatable in a fore-aft direction and that supports the front wheel; and a torsion reduction portion that reduces torsion of the oscillation unit (41, 341) in a vehicle width direction through the oscillation unit (41, 341) combined with the steering rotation unit (13, 313) under a condition in which the trail length (t) is changed such that the front wheel is disposed at a rearmost position, wherein the torsion reduction portion includes a fitted portion (90, 390) disposed in the steering rotation unit (13, 313) and a fitting portion (100, 300) that is disposed in the oscillation unit (41, 341) and that can be fitted in the fitted portion (90, 390), the fitting portion (100, 300) fits in the fitted portion (90, 390) under a condition in which the trail length (t) is changed such that the front wheel is disposed at the rearmost position, characterised in that the fitting portion is a protrusion protruding to a rear, and the fitted portion is a recess in which the protrusion fits..