An apparatus for collecting cleaning bodies in a tubular heat exchanger capable of collecting the cleaning bodies with a high collection efficiency against the temporary introduction of a large amount foreign matter such as falling tools in a cooling water system and against the deflected flow of the cooling water from the upstream side. A rectifying member rectifies or regulates the deflected flow of the cooling water from the upstream side whereby it is possible to collect the cleaning bodies without any adhesion and stagnation of the cleaning bodies in the cooling water on V-shaped collection lattices. It is also possible to trap a large article such as a falling tool between a guide member disposed downstream of the collection lattices and the collection lattices, and to introduce only the cleaning bodies into the guide member. Furthermore, the downstream port of a cleaning body discharge pipe opens toward the downstream side to thereby prevent the clogging of the port with the foreign matter or the like.
