To provide a coffee bag and its producing method which can be suitably used for preparing a larger amount of a coffee liquid or more concentrated coffee liquid.

The coffee bag with a gather on the bottom part imparts a structure capable of largely expanding a lower part of the bag by providing gathers on both sides of folded part of the bottom part of the coffee bag made of nonwoven cloth, and allows preparation of a larger amount of or more concentrated coffee liquid compared to a same size of bag with gathers on both sides.