A six-wheeled stretcher to be mounted in a vehicle for transporting a patient or the like, comprising: an upper frame for mounting a litter thereon; a front leg and a rear leg that each have an upper end axially attached to the upper frame, the upper end of the front leg being slidably and pivotally attached to a slide tube, the front leg further comprising a lower end to which is mounted to a front leg fixed caster; a rear auxiliary leg, the rear leg and a the rear auxiliary leg each comprising an upper end pivotably attached to the upper frame; a slide mechanism for assisting vertical movement of the position of the upper frame, the slide mechanism having a slide tube mounted to the upper frame for assisting vertical movement of the upper frame; wherein: a support arm for vertically holding an axis of a rotatable caster is axially attached at one end to a lower end of the rear auxiliary leg; the other end of the support arm is axially attached to a rear part of a link operation part of said rotatable caster; the rotatable caster and a lower end of the rear leg are pivotally attached to a front part of the link operation part, the link operation part supporting the rotatable caster; characterized in that the stretcher further comprises an auxiliary caster rotatably mounted to the front leg above the front leg fixed caster, wherein when an upper end of the front leg is slid backward and the front leg, the rear leg and the rear auxiliary leg are folded and fixed by rotating so as to lower the upper frame from a top stage to a lower stage, the axis of the rotatable caster is vertically held by the supporting arm and the front leg fixed caster floats from the ground surface so that the auxiliary caster and the rotatable caster contact the ground, thereby allowing movement in all directions. an upper frame for mounting a litter thereon; a front leg and a rear leg that each have an upper end axially attached to the upper frame, the upper end of the front leg being slidably and pivotally attached to a slide tube, the front leg further comprising a lower end to which is mounted to a front leg fixed caster; a rear auxiliary leg, the rear leg and a the rear auxiliary leg each comprising an upper end pivotably attached to the upper frame; a slide mechanism for assisting vertical movement of the position of the upper frame, the slide mechanism having a slide tube mounted to the upper frame for assisting vertical movement of the upper frame; a support arm for vertically holding an axis of a rotatable caster is axially attached at one end to a lower end of the rear auxiliary leg; the other end of the support arm is axially attached to a rear part of a link operation part of said rotatable caster; the rotatable caster and a lower end of the rear leg are pivotally attached to a front part of the link operation part, the link operation part supporting the rotatable caster; characterized in that the stretcher further comprises an auxiliary caster rotatably mounted to the front leg above the front leg fixed caster, wherein when an upper end of the front leg is slid backward and the front leg, the rear leg and the rear auxiliary leg are folded and fixed by rotating so as to lower the upper frame from a top stage to a lower stage, the axis of the rotatable caster is vertically held by the supporting arm and the front leg fixed caster floats from the ground surface so that the auxiliary caster and the rotatable caster contact the ground, thereby allowing movement in all directions.