A connecting device comprising at least one base body (12a, 12b; 112a, 112b) and at least one connecting unit (34; 134a, 134b) with - a fastening element (36; 136), - an adjustment body (38; 138) having a longitudinal axis, and - an adjustment device, wherein the distance between the fastening element (36; 136) and the base body (12a, 12b; 112a, 112b) is variable, wherein the base body (12a, 12b; 112a, 112b) has a wall with a first guide element, wherein the fastening element (36; 136) has a wall with a second guide element, wherein the wall of the base body (12a, 12b; 112a, 112b) on which the first guide element is provided and the wall of the fastening element on which the second guide element is provided face each other, wherein the adjustment body (38; 138) is arranged between the base body (12a, 12b; 112a, 112b) and the fastening element (36; 136) and has a first transverse side facing the base body (12a, 12b; 112a, 112b) and a second transverse side facing the fastening element (36; 136), wherein the adjustment body (38; 138) is displaceable by means of the adjustment device along an axis parallel to the longitudinal axis of the adjustment body (38; 138) and has a counter-guide element which interacts with the first or second guide element, and wherein the counter-guide element of the adjustment body (38; 138) is inclined with respect to the longitudinal axis of the adjustment body (38; 138), characterized in that the adjustment device comprises an adjustment rod (40; 140) and an adjustment means, the adjustment rod (40; 140) being rotatably connected to the adjustment body (38; 138), and in that a fixing element (68; 168) is provided in which the adjustment rod (40; 140) is mounted in a stationary and rotatable manner. - a fastening element (36; 136), - an adjustment body (38; 138) having a longitudinal axis, and - an adjustment device, wherein the distance between the fastening element (36; 136) and the base body (12a, 12b; 112a, 112b) is variable, wherein the base body (12a, 12b; 112a, 112b) has a wall with a first guide element, wherein the fastening element (36; 136) has a wall with a second guide element, wherein the wall of the base body (12a, 12b; 112a, 112b) on which the first guide element is provided and the wall of the fastening element on which the second guide element is provided face each other, wherein the adjustment body (38; 138) is arranged between the base body (12a, 12b; 112a, 112b) and the fastening element (36; 136) and has a first transverse side facing the base body (12a, 12b; 112a, 112b) and a second transverse side facing the fastening element (36; 136), wherein the adjustment body (38; 138) is displaceable by means of the adjustment device along an axis parallel to the longitudinal axis of the adjustment body (38; 138) and has a counter-guide element which interacts with the first or second guide element, and wherein the counter-guide element of the adjustment body (38; 138) is inclined with respect to the longitudinal axis of the adjustment body (38; 138), characterized in that the adjustment device comprises an adjustment rod (40; 140) and an adjustment means, the adjustment rod (40; 140) being rotatably connected to the adjustment body (38; 138), and in that a fixing element (68; 168) is provided in which the adjustment rod (40; 140) is mounted in a stationary and rotatable manner. wherein the distance between the fastening element (36; 136) and the base body (12a, 12b; 112a, 112b) is variable, wherein the base body (12a, 12b; 112a, 112b) has a wall with a first guide element, wherein the fastening element (36; 136) has a wall with a second guide element, wherein the wall of the base body (12a, 12b; 112a, 112b) on which the first guide element is provided and the wall of the fastening element on which the second guide element is provided face each other, wherein the adjustment body (38; 138) is arranged between the base body (12a, 12b; 112a, 112b) and the fastening element (36; 136) and has a first transverse side facing the base body (12a, 12b; 112a, 112b) and a second transverse side facing the fastening element (36; 136), wherein the adjustment body (38; 138) is displaceable by means of the adjustment device along an axis parallel to the longitudinal axis of the adjustment body (38; 138) and has a counter-guide element which interacts with the first or second guide element, and wherein the counter-guide element of the adjustment body (38; 138) is inclined with respect to the longitudinal axis of the adjustment body (38; 138), characterized in that the adjustment device comprises an adjustment rod (40; 140) and an adjustment means, the adjustment rod (40; 140) being rotatably connected to the adjustment body (38; 138), and in that a fixing element (68; 168) is provided in which the adjustment rod (40; 140) is mounted in a stationary and rotatable manner.