MULTILAYER FILTER MEDIUM FOR USE IN FILTER, AND FILTER

Provided are a multilayer filter medium for use in a filter, whichmakes it possible to obtain a filter having high collection efficiency, low pressure loss and a long filter lifetime, and a filter using the multilayer filter medium for use in a filter. A multilayer filter medium for use in a filter, which is used as a constituent member of a filter and has a multilayer structure, comprising a wet type nonwoven fabric layer A containing 0.5 to 20% by weight, based on layer weight, of short-cut nanofibers which are composed of a fiber-forming thermoplastic polymer, have a single fiber diameter (D) of 100 to 1,000 nm and are cut so that the ratio (L/D) of the length (L) to the single fiber diameter (D) is within the range of 100 to 2, 500 and core-sheath conjugate type binder fibers having a single fiber diameter of 5 µm or more, and a nonwoven fabric layer B having a lower density than that of the wet type nonwoven fabric layer A; and a filter using the multilayer filter medium for use in a filter and having the nonwoven fabric layer B arranged on a fluid inlet side.