Chest drainage device

According to the chest drainage device, one of a main machine and a collecting container is provided with a locking mechanism, and the other one is provided with a triggering piece. The locking mechanism comprises a locking piece, an unlocking piece used for unlocking the locking piece, a first elastic piece used for driving the locking piece to move in the locking direction and a limiting structure used for limiting the locking piece to the unlocking position. The locking piece and the limiting structure are movably arranged, when the trigger piece is inserted into the insertion position of the locking mechanism, the trigger piece drives the limiting structure to release the locking piece, and the first elastic piece drives the locking piece to move towards the locking position so as to lock the main machine or the collecting container. When unlocking is needed, a user can directly drive the locking piece to unlock through the unlocking piece, and therefore the main machine and the collecting container are s