POROUS FILTER

PROBLEM TO BE SOLVED: To provide a technology of making a thickness of a porous film uniform.SOLUTION: A porous filter includes a porous support body which has two end surfaces and has a flow passage passing from the one end surface to the other end surface, a first porous film formed on the porous support body, and a second porous film formed on a side where the first porous film does not face to the porous support body. The first porous film includes particles of different particle sizes formed of a same material, has a first local maximum value and a second local maximum value with 5% or more frequencies respectively when viewing particle size frequency distribution of the particles. A first particle size of the first local maximum value is larger than a second particle size of the second local maximum value. The first particle size is 2-7 times of the second particle size. The first particle size is 1-10 μm, and the second particle size is less than 1 μm.SELECTED DRAWING: Figure 2 【課題】多孔質膜の膜厚を均一にする技術を提供する。【解決手段】多孔質フィルターは、２つの端面を有し、一方の前記端面から他方の前記端面まで貫通する流路が形成された多孔質支持体と、前記多孔質支持体に形成された第１多孔質膜と、前記第１多孔質膜の、前記多孔質支持体に面していない側に形成された第２多孔質膜と、を備える多孔質フィルターであって、前記第１多孔質膜は、同一の材料から形成された粒径の異なる粒子を含み、前記粒子の粒径頻度分布を見たときに、頻度がそれぞれ５％以上である第１極大値と第２極大値とを有し、前記第１極大値の第１粒径は、前記第２極大値の第２粒径よりも大きく、前記第１粒径は、前記第２粒径の２倍から７倍であり、前記第１粒径は１μｍ以上１０μｍ以下であり、前記第２粒径は１μｍ未満である。【選択図】図２