This collecting apparatus collects foreign matter mixed in condensate in/from a condenser of a steam turbine plant, and comprises a first foreign matter collector and an in-condenser collector. The first foreign matter collector is provided on an upstream side of a condensate pump in a pipe connecting a drain outlet provided to the bottom portion of the condenser and the condensate pump to each other, has an opening having a first dimension, and collects foreign matter while passing the condensate therethrough. The in-condenser collector is provided inside the condenser, has an opening having a second dimension larger than the first dimension, and collects foreign matter while passing the condensate in the condenser therethrough toward the drain outlet.