Provided is a strainer including: a filter paper filtering fuel and having a space part disposed therein; an inner rib disposed inside the filter paper; protruding parts protruding up and down from the inner rib to be disposed inside the filter paper; and a communicating pipe combined with the filter paper to communicate with the space part. The filter paper and the inner rib are partially folded up longitudinally. The folded portion is formed in a rounded form, and the upper and lower portions of the filter paper are formed not to contact each other at the folded portion. Widths of the protruding parts are each formed differently and distances between the protruding parts are each formed differently. The width and the distance are more narrowly formed at the portion at which the filter paper is folded than at the portion at which the filter paper is not folded.