An electronic apparatus with a hidden antenna comprises a metal frame and a substrate. The metal frame comprises a plurality of side walls and a notch is passed through at least one side wall. A feeding terminal is configured at a bottom side of the notch. A first shorting terminal and a second shorting terminal are configured at two lateral sides of the notch. A metal surface of the substrate is electrically connected to the first shorting terminal, the second shorting terminal and the side walls, and the notch is faced to the substrate. The metal frame receives or transmits an electromagnetic signal, and delivers the electromagnetic signal over the feeding terminal, and a length of the bottom side of the notch is one half of a wavelength of the electromagnetic signal.