A mounting box, comprising: a longitudinal centre axis (X-X), a bottom part, being formed of a bottom portion and a connection portion, said bottom portion forming a bottom of the mounting box and having at least one pre-prepared point (18A, 18B) for a tube and/or cable lead-in, a separate top part (20, 30) being connectable to the bottom part, the top part (20, 30) being formed of a tubular body portion (21, 31) with a first end (21A, 31A) and an axially (X-X) opposite second end, the bottom part and the top part (20, 30) are connected to each other through first connection means positioned in connection with the bottom part and second connection means positioned in connection with the top part, characterized in that the first end (21A, 31A) of the tubular body portion (21, 31) of the top part (20, 30) is provided with radially outwardly from the body portion (21, 31) extending flange means (22, 32), and fastening means (220, 230) cooperating with the flange means (22, 32) in order to fasten the mounting box to a wall, the bottom part is adapted to be pushed in the axial (X-X) direction at least partly into the top part (20, 30) so that an opening is formed through the body portion (21, 31) of the top part (20, 30) into a mounting space formed in the interior of the mounting box, the first connection means comprises a radially directed groove on an outer surface of the connection portion of the bottom part, the second connection means comprises a radially inwardly directed notch on the second end of the top part, whereby a snap locking is achieved between the bottom part and the top part when the notch of the second connection means seats into the groove on the first connection means. a longitudinal centre axis (X-X), a bottom part, being formed of a bottom portion and a connection portion, said bottom portion forming a bottom of the mounting box and having at least one pre-prepared point (18A, 18B) for a tube and/or cable lead-in, a separate top part (20, 30) being connectable to the bottom part, the top part (20, 30) being formed of a tubular body portion (21, 31) with a first end (21A, 31A) and an axially (X-X) opposite second end, the bottom part and the top part (20, 30) are connected to each other through first connection means positioned in connection with the bottom part and second connection means positioned in connection with the top part, characterized in that the first end (21A, 31A) of the tubular body portion (21, 31) of the top part (20, 30) is provided with radially outwardly from the body portion (21, 31) extending flange means (22, 32), and fastening means (220, 230) cooperating with the flange means (22, 32) in order to fasten the mounting box to a wall, the bottom part is adapted to be pushed in the axial (X-X) direction at least partly into the top part (20, 30) so that an opening is formed through the body portion (21, 31) of the top part (20, 30) into a mounting space formed in the interior of the mounting box, the first connection means comprises a radially directed groove on an outer surface of the connection portion of the bottom part, the second connection means comprises a radially inwardly directed notch on the second end of the top part, whereby a snap locking is achieved between the bottom part and the top part when the notch of the second connection means seats into the groove on the first connection means.