The subject innovation is to compressed air to be supplied to various industrial pneumatic device by the compressor passes through the elements of the air filter is a foreign matter such as dust, moisture contained in the air with the water droplets from the water agglomeration during filtration outside the waste water which collects in the jipsugu It relates to a combination of automated and manual drain device for the air filter to be discharged to. Drain device of a conventional air filter it will cost to be automatically operated only not as soon as it takes a lot of production cost mothayeo not a rational structure as well as not operate the air filter into the drain by the high pressure in the jipsugu prolonged continued use automatic sewage in jipsugu It has been followed many uncomfortable doemeuro not been a large amount together or when automatic drain device can discharge the sewage in the jipsugu by manual operation at the time of failure. Known present design is between the inlet (1A) and an outlet (1B), a body (1) forming the hole 501 is perforated the cover (5) and to cover (5) in order to solve the above jipsugu fixed to the base plate 6, the filter paper 7, a glass fiber (8), urethane foam fixed to the body cover to a body cover (2) intergranular the element 4 is brought into contact in turn (9) (2) ( 3) within the lower portion of the packing 11 and the hole (10A) is a perforated cover 10, the fixing bolts 12 and fixing nuts (fixing the fixing bolts (12, 13)) is an O-ring 15 is fixed according to the one by Tan to the discharge hole 140 is perforated hose plug 14 in the spring 16, In the cover 10 is emitted burnt the valve 19 is fixed to the operating rod 18 within the cylinder 17 to secure the cylinder 17 to form the inlet 170 to the spring 20 hole 210 is perforated (220 of the guide tube for fixing in 21 the V-packing 24 and the piston 22 forms a valve seat 23 is fixed and the concave inlet (22A) and the contact surface (22B) ) for fitting the operating rod 18 a spring 25 in the elastic by concave inlet (22A) and into the hole 220 of the piston 22 forms a contact surface (22B) on the actuating rod (18) spring (25, ) and the elastic by concave inlet (22A) and the contact surface (22B) so that the can jeoptal the V packing 26 of the fixing bolt 12, End portion, and has a float (29 sealing plate above the sealing plate was fixed to 28, 28 of the cylinder the upper valve seat 27, hole 270, tube release Keene operating rod 18 to the outside of the fixed to the 17 ) for fixing to jipsugu (3) an amount of a by a buoyant float (29 becomes waste water) at the same time and sangseungdoem and sewage is discharged to the outside when there is a malfunction or a need to artificially discharge the waste water, such as the float (29) hose to the waste water, by which to simply raise the plug (14) is one to be manually released.