To provide a waste liquid recovery device and a waste liquid recovery method, in which pre-treatment and after-treatment are simple, and by which a waste liquid can be recovered regardless of conditions on the ground.

An adsorber 4 which can be freely brought into contact with the wall surface and separated from the wall surface by the operation of a pressure reducing means is removably fitted to a nacelle 3, and when the pressure reducing means is operated, the nacelle 3 is brought into close contact with the wall surface to be cleaned to introduce the waste liquid flowing from above into the nacelle 3 and further recover the same on the ground.