A cassette assembly and a method of manufacturing fluorescent lamps using the cassette assembly are provided. The cassette assembly includes a housing defining a process chamber and having a plurality of holes in which glass tubes for the fluorescent lamps are inserted to communicate with the chamber, a carrying unit including two or more porous plates through which the glass tubes are fitted, a plurality of ring members disposed on the porous plates to preliminarily fix the glass tubes to the carrying unit by allowing the outer circumferences of the glass tubes to contact, and a locking unit for changing the glass tubes from the preliminary fixing status to a lockup status by varying contact pressure applied between the ring members and the glass tubes.