A walking aid wheelchair , comprising: a chassis , a movable base plate which is movable relative to the chassis between a low sitting position in which a user (U) can sit thereon, and a high walking position in which it is configured to be in contact with the user (U) and at least partially behind the user (U), a position changing device for the base plate, configured to move the base plate between its high position and its low position, the position changing device comprising at least one first arm (41 G , 41 D ) extending between the chassis and the base plate , and a linear actuator (44 G , 44 D ) which is connected through a lower mechanical connection to the chassis and by an upper mechanical connection to the first arm (41 G , 41 D ), the linear actuator (44 G , 44 D ) being configured to bias the movable base plate to the high position through the first arm (41 G , 41 D ), characterised in that the first arm (41 G , 41 D ) is connected at its lower end through a lower hinge to the chassis and at its upper end through an upper hinge to the movable base plate , the upper hinge being located behind the lower hinge over the entire stroke of the movable base plate when the movable base plate moves from the low position up to the high position, and the first arm (41 G , 41 D ) forming a third class lever. a chassis , a movable base plate which is movable relative to the chassis between a low sitting position in which a user (U) can sit thereon, and a high walking position in which it is configured to be in contact with the user (U) and at least partially behind the user (U), a position changing device for the base plate, configured to move the base plate between its high position and its low position, the position changing device comprising at least one first arm (41 G , 41 D ) extending between the chassis and the base plate , and a linear actuator (44 G , 44 D ) which is connected through a lower mechanical connection to the chassis and by an upper mechanical connection to the first arm (41 G , 41 D ), the linear actuator (44 G , 44 D ) being configured to bias the movable base plate to the high position through the first arm (41 G , 41 D ), characterised in that the first arm (41 G , 41 D ) is connected at its lower end through a lower hinge to the chassis and at its upper end through an upper hinge to the movable base plate , the upper hinge being located behind the lower hinge over the entire stroke of the movable base plate when the movable base plate moves from the low position up to the high position, and the first arm (41 G , 41 D ) forming a third class lever. the position changing device comprising at least one first arm (41 G , 41 D ) extending between the chassis and the base plate , and a linear actuator (44 G , 44 D ) which is connected through a lower mechanical connection to the chassis and by an upper mechanical connection to the first arm (41 G , 41 D ), the linear actuator (44 G , 44 D ) being configured to bias the movable base plate to the high position through the first arm (41 G , 41 D ), characterised in that the first arm (41 G , 41 D ) is connected at its lower end through a lower hinge to the chassis and at its upper end through an upper hinge to the movable base plate , the upper hinge being located behind the lower hinge over the entire stroke of the movable base plate when the movable base plate moves from the low position up to the high position, and the first arm (41 G , 41 D ) forming a third class lever. <EOS>