The problem addressed by the present invention is to provide a backflushable depth filter. Provided is a hollow cylindrical depth filter formed from thermoplastic resin fiber with a fiber medium thickness of 5 - 25 mm, wherein: the compression ratio of the filter medium when a load of 0.5 MPa is applied is 0.2 or less; the filter medium has at least three fiber layers from a fluid inflow side to afluid outflow side; the void fraction of the first layer on the fluid inflow side is in a range of 0.70 - 0.85, the void fraction of the second layer on the fluid inflow side is in a range of 0.60 -0.80, and the void fraction of the third layer on the fluid inflow side is in a range of 0.70 - 0.85; the void fraction of the first layer is greater than the void fraction of the second layer, and the void fraction of the third layer is greater than the void fraction of the second layer; intersecting points of the fibers constituting the fiber medium are joined; the average interval for the intersecting points of the fibers is 2 - 100 times the average fiber diameter in the direction of length of fibers; and the ratio of the average fiber diameter for the upstream-side surface of the filter medium and the average fiber diameter for the downstream-side surface is 0.9 - 1.2 times.