To stably perform waste liquid discharge operation without causing clogging by arranging a switching type branch part in an upper part of a hollow vessel, and arranging a check valve to keep the inside of a body cavity under negative pressure in a separate position of the branch part.

A medical discharge device has a switching type branch part 2 to switch an inflow port 3 and an abondoning port 4 to communicate gas- liquid with a vessel 1 in an upper part of the vessel 1 to store a waste liquid 12, and has an aspirator connecting port 6 where a check valve 5 is arranged in a separate upper part of the vessel 1. The discharge device is used by connecting a catheter 11 detained in a body cavity to the inflow port 3. When switching abandoning operation is performed on the switching type branch part 2, since an inflow passage from a body cavity is closed, the inside of a thoracic cavity is kept under gnegative pressure particularly when it is used for discharge in a thoracic cavity, and abandoning operation can be safely performed.