A non-contact communication antenna unit capable of implementing a thickness reduction of a mobile communication device and also suppressing a reduction in a communication range characteristic of a non-contact communication antenna even when metal components such as circuit wirings, a circuit GND, a shielding case, etc. being arranged on the inside of the mobile communication device are arranged in close vicinity to the non-contact communication antenna is provided.A non-contact communication antenna 9 and a magnetic sheet 11 arranged on one surface of a non-contact communication circuit board 8 respectively, and an non-contact communication electronic components 10 and a magnetic sheet 12 arranged on the other surface of the non-contact communication circuit board 8 respectively are provided, whereby the magnetic sheet 11 and the magnetic sheet 12 are arranged on the non-contact communication circuit board 8 such that the non-contact communication antenna 9 and the non-contact communication electronic component 10 are separated mutually.