PURPOSE: To perform the mass production of circular filter paper generating no deformation, by a method wherein an adhesive is applied to both end parts opposed to each other of filter paper moved by a feed apparatus and both end parts of said paper are brought into contact with each other under pressure in a mutually approaching direction by a pressure contact device.

CONSTITUTION: Filter paper formed into a ring shape and having a large number of pleats is supported by a support stand 100 and moved between a mounting and detaching position, where the filter paper 10 is arranged on the support stand 100, and a working position, where an adhesive is applied to the filter paper, by a feed apparatus 200. Further, in an adhesive applying apparatus 400, and adhesive is applied to both end parts opposed to each other of the filter paper 10. A pressure contact apparatus 500 having a pair of opposed pressure contact plates 501A, 501B supports both end parts of the filter paper 10 and presses both end parts coated with the adhesive of the filter paper 10 in a mutually approaching direction. As a result, the mass production of the circular filter paper generating no deformation becomes possible.