Antenna device, communication module, portable electronic apparatus, and communication method using portable electronic apparatus

The present invention addresses the issue of providing an antenna device, which has wide-angle directivity, and a configuration suitable to be used in a portable electronic apparatus. An antenna device (100) of the present invention is provided with a flat board-like substantially rectangular soft magnetic body (200), and a loop-shaped coil (330). The coil (330) is disposed from the front surface (212) to the rear surface (214) of the soft magnetic body (200) such that a region surrounded by the coil (330) includes at least a part of a specific edge (216), i.e., one edge out of four edges of the soft magnetic body (200), and does not include a facing edge (218) that faces the specific edge (216).