The stiffening device for an electronics cabinet (1) has two angle struts (6, 7) which are supported in each case at their limb ends by means of spherical shell joints (10) in mutually opposite corners (8a, 8b; 9a, 9b) of a door opening of the framework (3) of the electronics cabinet (1), such that they can pivot about a rotation axis (11, 12) which is parallel to the side edges of the framework (3). In order to be able to suspend each angle strut (6, 7) easily in the framework (3) or remove it from the framework (3), each spherical shell (10a) has a slot (10b) which runs radially out from its centre point and whose width is greater than the thickness of the profiled rods of the associated angle strut (6 or 7 respectively). Each slot (10b) opens into an opening (10c) which is adjacent to the framework (3) and whose cross-section is greater than the cross-section of the ball-headed pins (10d) of the associated angle strut (6 or 7 respectively). The spherical shells (10a) are mounted on the framework (3) for each angle strut (6 or 7 respectively) such that their slots (10b) are aligned with one another and open towards the exterior. <IMAGE>