To provide a diaper bag that can be easily attached to and detached from a strap for holding infant and in/from which items can be easily put and taken out while an infant is held with the strap for holding infant.

A diaper bag forms a storage part with a back face part, a front face part, side face parts, and a bottom face part and provides an upper opening part. To each of a right edge and a left edge of an upper part of the diaper bag body back face part, an upper part of a tape and a buckle as coupling means and a lower part of the tape and a tongue are provided. A rubber string is inserted into the upper opening part of a diaper bag body front face side. A pocket is provided in a diaper bag body side face part, a zipper, which opens and closes an opening, is attached to the opening of the pocket, and the pocket is sewn to a diaper bag body back face inner side.