A wireless power relay apparatus coupling case comprising: a case of an electronic apparatus; and a wireless power relay apparatus coupled to the case, and disposed between the electronic apparatus and a wireless charging apparatus to transfer received power to the electronic apparatus at the time of performing charging, wherein the wireless power relay apparatus comprises: a substrate; a coil formed on the substrate; characterised in that an impedance matching circuit is electrically connected to the coil wherein the impedance matching circuit includes: an impedance matching unit having various impedance values preset through capacitors and resistors; a controlling unit selecting an appropriate impedance value from the impedance matching unit depending on a state of wireless power received by the coil; a rectifying unit rectifying the wireless power received by the coil and supplying the rectified power to the controlling unit; a detecting unit sensing a current rectified by the rectifying unit to detect a state of a wireless power transmission signal and transmit the detected state of the wireless power transmission signal to the controlling unit; and a switching unit selecting an impedance value of the impedance matching unit depending on a control of the controlling unit, wherein the case includes a body case coupled to the electronic apparatus and a cover covering a front surface of the electronic apparatus, the wireless power relay apparatus is embedded in the case and attached to one surface of the cover, and the cover is folded toward a rear surface of the electronic apparatus at the time of performing charging. a case of an electronic apparatus; and a wireless power relay apparatus coupled to the case, and disposed between the electronic apparatus and a wireless charging apparatus to transfer received power to the electronic apparatus at the time of performing charging, wherein the wireless power relay apparatus comprises: a substrate; a coil formed on the substrate; characterised in that an impedance matching circuit is electrically connected to the coil wherein the impedance matching circuit includes: an impedance matching unit having various impedance values preset through capacitors and resistors; a controlling unit selecting an appropriate impedance value from the impedance matching unit depending on a state of wireless power received by the coil; a rectifying unit rectifying the wireless power received by the coil and supplying the rectified power to the controlling unit; a detecting unit sensing a current rectified by the rectifying unit to detect a state of a wireless power transmission signal and transmit the detected state of the wireless power transmission signal to the controlling unit; and a switching unit selecting an impedance value of the impedance matching unit depending on a control of the controlling unit, wherein the case includes a body case coupled to the electronic apparatus and a cover covering a front surface of the electronic apparatus, the wireless power relay apparatus is embedded in the case and attached to one surface of the cover, and the cover is folded toward a rear surface of the electronic apparatus at the time of performing charging. a substrate; a coil formed on the substrate; characterised in that an impedance matching circuit is electrically connected to the coil wherein the impedance matching circuit includes: an impedance matching unit having various impedance values preset through capacitors and resistors; a controlling unit selecting an appropriate impedance value from the impedance matching unit depending on a state of wireless power received by the coil; a rectifying unit rectifying the wireless power received by the coil and supplying the rectified power to the controlling unit; a detecting unit sensing a current rectified by the rectifying unit to detect a state of a wireless power transmission signal and transmit the detected state of the wireless power transmission signal to the controlling unit; and a switching unit selecting an impedance value of the impedance matching unit depending on a control of the controlling unit, wherein the case includes a body case coupled to the electronic apparatus and a cover covering a front surface of the electronic apparatus, the wireless power relay apparatus is embedded in the case and attached to one surface of the cover, and the cover is folded toward a rear surface of the electronic apparatus at the time of performing charging. an impedance matching unit having various impedance values preset through capacitors and resistors; a controlling unit selecting an appropriate impedance value from the impedance matching unit depending on a state of wireless power received by the coil; a rectifying unit rectifying the wireless power received by the coil and supplying the rectified power to the controlling unit; a detecting unit sensing a current rectified by the rectifying unit to detect a state of a wireless power transmission signal and transmit the detected state of the wireless power transmission signal to the controlling unit; and a switching unit selecting an impedance value of the impedance matching unit depending on a control of the controlling unit, wherein the case includes a body case coupled to the electronic apparatus and a cover covering a front surface of the electronic apparatus, the wireless power relay apparatus is embedded in the case and attached to one surface of the cover, and the cover is folded toward a rear surface of the electronic apparatus at the time of performing charging.