The invention relates to an apparatus for exercising and supporting an upper limb, the apparatus comprising two support modules (A, B) connected on the first side by a rigid connecting piece (5). Both the support modules (A, B) have a frame (1), with a support plate (4) fixed to their upper part. An exercising part (C) has been removably attached to the support plate of the first support module (A), the exercising part (C) comprising an upper arm support means (3) articulated in the support plate (4; 4a) and an actuator (9) actuating said support means relative to the support plate. The invention also relates to an arrangement using the apparatus above. In the arrangement, the frames (1) of the support modules (A, B) can be fitted immediately underneath the shoulder joints (N), the other upper limb being supported on the support plate (4; 4b) fixed to the upper part of the frame (1; 1b) of the second support module (B) in such a way that the upper limb exerts a force (F1) on the rigid connecting piece (5). The first upper limb that has undergone surgery is supported on the exercising part (C) fixed to the support plate (4; 4a) disposed in the upper part of the frame (1; 1a) of the support module (A) in a way such that the weight of the upper limb exerts a force (F2) on the rigid connecting piece (5), the forces (F1) and (F2) being balanced by means of the connecting piece (5).