To provide a filter for a gas generator of low cost and good performance, and to provide the gas generator using the filter.

A thin metal plate of thin plate thickness is wound in coil shape to form a wound body 30. The wound body 30 is held to a rotating holder 31 and rotated around the axis of the wound body 30 by a driving device. A cutting tool 32 is pressed to the end face of the wound body, and the cutting tool 32 is fed at constant speed in a parallel direction to the axis of the wound body 30. The wound body 30 is cut in such a manner as to be chipped off thin from the end face to manufacture fine metallic fiber 33. The fiber 33 is knitted or plain-woven to form the filter.