The present invention provides a rainwater catchment apparatus 1 that is easily installed without renovating a building. The rainwater catchment apparatus 1 comprises a rainwater inlet 7 for introducing rainwater, a flange portion 10 engaged with a peripheral portion of a rainwater outlet 3 serving as a leading end of a drainage canal 4 formed in a building framework 2 for introducing rainwater into the rainwater inlet 7, a drain portion 9 for discharging excessive water exceeding a predetermined level to the drainage canal 4, a reservoir 5 freely fitted into the drainage canal 4 through the rainwater outlet 3, and a pumping mechanism 6 for pumping water stored in the reservoir 5 to the outside.
