To reduce the number of parts and the quantity of adhesive used in a connecting part of a bypass element and a full flow element by holding the body of a flow passage on the one end side of a connecting tubular body and pressing and holding the other end side of the connecting tubular body by a separate cylindrical body pressed by a cylindrical body and a panel member.

An integrated body of a plate spring 15 and a relief valve 16 is housed in a case and the filter body 13 of a full flow element is mounted on the plate spring 15, and also the peripheral wall 13c-1 and the annular projection 13c-2 of an end plate 13 on the one end side are engaged with the stepped part of a connecting tubular body 17. And, the flange part 17b of the connecting tubular body 17 is engaged with the bulged part 12b-1 of the other end side 12b in the filter body 12 of a bypass element. Furthermore, after a valve disc is mounted on an end plate 12a on the one end side, an filtered oil delivery tubular body is inserted into a fitting hole of the valve disc to fit it in a bulged part 12a-1 of the end plate 12a. The filter bodies 12, 13 are held by a closing plate through the plate spring 15 and the valve disc.