To allow refuse to be thrown into a refuse pit efficiently and a large volume of refuse to be stored in the refuse pit.
A platform 4 communicating with a refuse pit 2 through a refuse pit door 3 at the sidewall part of the refuse pit 2 is provided on the ground level G.L at the front part of a factor building 1. The platform 4a is provided in the up side of the platform 4, and the refuse pit door 3a is arranged at the sidewall part of the refuse pit facing the platform 4a. Refuse 6 can be thrown into the refuse pit 2 from the top of the platforms 4 and 4a on the two floors in a vertical direction to be stored. When a refuse storage quantity is increased, the refuse pit door 3 is closed to use up to the height zone of the first-floor platform 4 as the refuse pit 2.