The present invention relates to a wheelchair comprising a structure (1) defining a seat area (2) limited by a rear backrest (3) and two parallel side walls (4 and 5) and has larger side wheels (6 and 7) and smaller front wheels (8). One of the larger side wheels (6) is movable with respect to the structure (1) and is assembled on said structure through two arms, one fixed arm (9) and another mobile arm (10), the fixed arm of which is integral to one of the sides of the structure (1) in horizontal position and protrudes from the rear of said structure into a portion to the end of which the mobile arm is articulated according to a vertical shaft (11) and the mobile arm (10) of which has the mobile side wheel (6) assembled on its free end and it can pivot about the articulation shaft (11).
