Construction unit (1) for building up a frame (2), wherein the frame (2) comprises at least two girders (3a, 3b) and multiple uprights (4), wherein the construction unit (1) comprises a first construction profile (4), a second construction profile (5) and a third construction profile (6), wherein the first construction profile (4) is provided to serve as an upright (4) and the second and the third construction profile (5, 6) are each provided to be part of a respective girder (3a, 3b), wherein each construction unit (1) is provided to form only one upright (4) of a frame (2) and that multiple such construction units (1) are provided to be successively interconnected so that the first construction profiles (4) of successively construction units (1) extend at a distance from one another.