Abstract: A screw clamp comprises a pillar (5), a backing arm (11) and a clamping arm (12), a clamping part (6) being connected with the backing arm (11) and/or with the clamping arm (12) and a respective thrust plate (7 and 8) being connected with the backing arm (11) and with the clamping arm (12) or, respectively, with the clamping part (6). In order to render it possible to exert forces on surfaces which are not parallel to each other the backing arm thrust plate (8) and/or the clamping arm thrust plate (7) are adjustable in angle, preferably because the backing arm (11) and/or the clamping arm (12) respectively consist of an arm bearing (1 and 2) and an arm shank (3 and 4) able to be turned in relation to it.