The invention relates to a loading system for introducing a filling material such as an annular catalyst body into a tubular reactor, wherein the loading system comprises a filling device. The invention is characterized in that the loading system comprises at least a host or at least a tube which has an outer end part outside the tubular reactor and an inner end part in the inner space of the tubular reactor and is suitable for conveying the filling material to the inner space through an opening in the tubular reactor. The invention also relates to a method for filling the tubular reactor by using the loading system. The method includes the steps of: a) filling an external front room of which a box can be exchanged with a defined amount of the filling material; and b) introducing the filling material into the at least one host or at least tube which introduces the filling material to the inner space through the opening.