The present invention relates to a removable device (1) for stabilizing a wheelchair (2) comprising at least one chassis (3), large rear wheels (4) mounted so as to rotate freely on an axle secured to said chassis (3) and small, pivoting front wheels (4)； said device is noteworthy in that it comprises at least one arm (6) provided at a first end of a secondary wheel (7) and, between its opposite end and the central part of the arm (6), removable securing means (8) that engage with the hub of one of the rear wheels (4) of the wheelchair (2) and means (9) for moving the secondary wheel (7) from a retracted position in which said secondary wheel (7) extends above the ground to an active position in which the secondary wheel (7) presses against the ground, and vice versa. Another subject of the invention relates to a wheelchair equipped with at least one stabilizing device according to the invention.
