It is provided that a pre-air-filter, for an internal combustion engine, which allows stiffness to be assured even when the weight is reduced, which also has excellent dust holding properties, and which has an excellent resistance to entry of water. A pre-air-filter for an internal combustion engine (1) contains a nonwoven fabric comprising a first fiber having a melting point of not lower than 80° C. and not higher than 200° C., a second fiber having a melting point of higher than the melting point of the first fiber by not less than 30° C., being crimped, and having a hollow structure, entanglement of the first fiber and the second fiber by needle punching, and fusion of partly or entirely melted first fiber and the second fiber. This pre-air-filter (1) is installed at an air-inlet-side of a main-air-filter (2).