An oil filter includes a filter body including first and second plates stacked to each other, the first plate including a plurality of filtration holes, the second plate including a plurality of passage holes, an inner diameter of the passage holes being greater than an inner diameter of the filtration holes, the filtration holes facing the respective passage holes. Further, the first plate and the second plate are bonded to each other in a manner that a whole area of openings of the filtration holes is arranged within a range of openings of the passage holes.
