Abstract: An apparatus for forming films by evaporation in vacuum has a chamber for evaporating a coating material containing a coating material (10), and a heating element (2) positioned outside this chamber. A collimating chamber (3), which is identically constructed, communicates with the chamber (1), and each of the chambers (1,3) has a pair of ports (4, 5) aligned on an axis (8), a socket pipe (6,7) being received in one of the ports, respectively, the socket pipe (6) of the evaporation chamber (1) being received in the port (5) of the collimating chamber (3), the evaporation chamber (1) having a sealing member (9) provided in the other port (4) of the chamber (1).