To provide a method for producing a filament nonwoven fabric which do not slip, when subjected to an interlacing treatment, and can give artificial leather substrates and artificial leathers high in qualities for bents and wrinkles, and to provide a method for producing a substrate for artificial leathers.

This method for producing the filament nonwoven fabric is characterized by continuously comprising a web-forming process for spinning ultra fine-forming type filaments and collecting the ultra fine-forming type filaments on a net to form webs, a fusing treatment process for applying a fusing treatment to the webs, a lamination process for laminating the fused webs to form a laminated web, and an interlacing process for contacting at least one surface of the laminated web with a part of the surface member of an interlacement apparatus and simultaneously interlacing with an interlacing treatment member in the interlacement apparatus in the contact portion, wherein the direction for driving the surface member in the contact portion is identical to the direction for conveying the laminated web in the interlacing treatment, and the driving speed is approximately identical to the conveying speed.