To provide a filter of which the purifying function is enhanced by raising raw water through a filter medium by utilizing siphon effect.

This filter consists of a raw water receiver 1 having rough filtering function and a filter main body 2. The filter main body 2 consists of the water guide part 3 provided to the outer periphery thereof, the purified water drain pipe 5 arranged to the central part thereof and the filter medium housing part 6 arranged between the water guide part 3 and the drain pipe 5 and the raw water flowing down from the raw water receiver 1 is allowed to flow down from the water guide part 3 and raised through the filter medium housing part 6 from the lower part of the water guide part 3 to be filtered and purified water is gathered from the upper part of the filter medium housing part 6 to be allowed to flow down from the upper part of a purified water drain pipe 5 to be taken out of the lower part thereof.