This invention relates to a bag filter having a tubular section, one closed end and one open end, the tubular section having a nonwoven felt comprising an intimate fiber blend of 50 to 80 parts by weight polyphenylene sulfide fiber and 20 to 50 parts by weight acrylic fiber, based on the total weight of polyphenylene sulfide and acrylic fibers in the felt, wherein the acrylic fiber has an equal or lower denier per filament than the polyphenylene sulfide fiber.