A work vehicle comprising: a vehicle body; a plurality of traveling devices for driving traveling disposed on the right and left sides on the front and rear sides of the vehicle body respectively; a plurality of articulated link mechanisms each comprising a plurality of links pivotally connected to each other to provide at least two or more joints and configured to support each one of the traveling devices to the vehicle body with allowing lifting up/down thereof; and a drive operating device capable of changing postures of the articulated link mechanisms; wherein a first link included in the plurality of links and located closest to the vehicle body is supported to be pivotable about a horizontal axis with its body side coupling portion acting as a pivot; wherein there is provided a manual operation type position fixing device capable of selectively fixing the first link at any one of a plurality of preset pivot switching positions; wherein the position fixing device is configured to fix the first link in position to one of a vertically oriented position at which the first link assumes an approximately perpendicular posture, an inward pivotal position at which the first link is pivoted for a set amount toward an inner side in a vehicle body front/rear direction relative to the vertically oriented position, and an outward pivotal position at which the first link is pivoted for a set amount toward an outer side in the vehicle body front/rear direction relative to the vertically oriented position; wherein the drive operating device is configured to change the posture of another link included in the plurality of links than the first link; characterised in that the first link integrally forms a retaining functional portion, wherein an insertion hole is formed to extend through the retaining functional portion in the right/left direction; wherein the position fixing device has a restriction member which is integrally coupled and fixed to the base end portion of the bending link mechanism, and position restriction engagement holes are defined in the restriction member and extend therethrough in a vehicle right/left direction, at respective positions to which the insertion hole formed in the first link comes into opposition when the first link is switched to any one of the vertically oriented position, the inward pivotal position and the outward pivotal position, respectively. a vehicle body; a plurality of traveling devices for driving traveling disposed on the right and left sides on the front and rear sides of the vehicle body respectively; a plurality of articulated link mechanisms each comprising a plurality of links pivotally connected to each other to provide at least two or more joints and configured to support each one of the traveling devices to the vehicle body with allowing lifting up/down thereof; and a drive operating device capable of changing postures of the articulated link mechanisms; wherein a first link included in the plurality of links and located closest to the vehicle body is supported to be pivotable about a horizontal axis with its body side coupling portion acting as a pivot; wherein there is provided a manual operation type position fixing device capable of selectively fixing the first link at any one of a plurality of preset pivot switching positions; wherein the position fixing device is configured to fix the first link in position to one of a vertically oriented position at which the first link assumes an approximately perpendicular posture, an inward pivotal position at which the first link is pivoted for a set amount toward an inner side in a vehicle body front/rear direction relative to the vertically oriented position, and an outward pivotal position at which the first link is pivoted for a set amount toward an outer side in the vehicle body front/rear direction relative to the vertically oriented position; wherein the drive operating device is configured to change the posture of another link included in the plurality of links than the first link; characterised in that the first link integrally forms a retaining functional portion, wherein an insertion hole is formed to extend through the retaining functional portion in the right/left direction; wherein the position fixing device has a restriction member which is integrally coupled and fixed to the base end portion of the bending link mechanism, and position restriction engagement holes are defined in the restriction member and extend therethrough in a vehicle right/left direction, at respective positions to which the insertion hole formed in the first link comes into opposition when the first link is switched to any one of the vertically oriented position, the inward pivotal position and the outward pivotal position, respectively. the first link integrally forms a retaining functional portion, wherein an insertion hole is formed to extend through the retaining functional portion in the right/left direction; wherein the position fixing device has a restriction member which is integrally coupled and fixed to the base end portion of the bending link mechanism, and position restriction engagement holes are defined in the restriction member and extend therethrough in a vehicle right/left direction, at respective positions to which the insertion hole formed in the first link comes into opposition when the first link is switched to any one of the vertically oriented position, the inward pivotal position and the outward pivotal position, respectively.