Abstract: The invention relates to a collapsible wheelchair or carriage of the stroller type, particularly for handicapped children. The carriage has a rectangular, rigid under-frame, formed by two side members (1) with wheeled axles (2) joining the members, which also support a superstructure (5, 7, 9). The superstructure is collapsible from an erected position of use to a folded position adjacent the underframe, and carries the carriage seat (15), which includes a seat portion (15a) and a back portion (15b) and preferably side pieces as well. The superstructure is self-locking in an erected state, such that it cannot be collapsed under the action of the weight of a person sitting in the seat. The superstructure is also implemented to form armrests or side supports for the seat.