To make the whole antenna module thinner and prevent unevenness of transmission performance.

An antenna module 10 includes a loop-shaped antenna coil 14 formed on an insulating substrate 12, a ferrite core 18 formed on an upper face side at an inner layer of the insulating substrate 12, and a Liqualloy sheet 20 prepared with space on the lower face side in the inner layer of the insulating substrate 12. The antenna coil 14 generates magnetic field for communication at an upper face of the insulating substrate 12 at the time of communication. The generated magnetic field is enclosed with ferrite core 18 and the Liqualloy sheet 20, so leak of magnetic field to exterior can be prevented.