Abstract: A wheelchair is disclosed in which a body support frame pivoted to a main frame can move from a seated posture to a stand-up posture and vice versa without using an external elevating force. The wheelchair includes the main frame for supporting driving wheels and auxiliary wheels and a body support frame formed by interconnecting a lower limb support member, a waist support member and a back rest member to one another. The forward portion of the main frame and the tip portion of the waist support member are turnably supported by a pivot, and an extension member for turnably supporting the waist support member with the pivot as the support point is interposed between the main frame and the waist support member. The motive force for the stand-up operation of the body support frame relies upon the push-up force of the user of the wheelchair (the body lift-up force of the user by his or her upper limbs) and the force of the extension member.