Drain trap

A drain trap comprising:

• a main body which has a tubular shape with a closed end and which includes an inner space communicated with a receiving unit and a discharge unit;
• a lid which covers the inner space;
• and
• a partition which partitions the inner space into a storage space and a discharge space, where the storage space stores liquid received from the receiving unit and the discharge space discharges liquid to the discharge unit,
• wherein the partition includes a tubular first partition and a second partition extending outward from around the circumference of the first partition, and can be inserted into the inner space,
• sealing units are installed all around circumferences of the partition and a side wall of the main body to bring part of the second partition into intimate contact with part of the side wall by exerting a vertical force component under a vertical pressing force,
• a slanting contact portion is provided for receiving the vertical pressing force to come into contact with at least part of the sealing units, and
• the partition is equipped with a valve disc which floats up to allow liquid to flow from the storage space to the discharge space when the liquid in the storage space reaches or exceeds a set amount as well as with a valve seat which catches and supports the valve disc.