A heat generating device includes an air-permeable first side located proximal to a wearers body, a second side located distal to a wearers body, and a heat generating member between the two sides. The second side includes an adhesive layer for attaching the device to a garment. The first side is formed of a nonwoven fabric having an uneven surface topography. The nonwoven fabric includes a first fiber layer, inclusive of a first surface of the fabric, and a second fiber layer, inclusive of a second surface of the fabric, partly bonded to each other and including a large number of protrusions and recesses on the side of the first fiber layer. The first surface is used as the first side.
