According to one embodiment, an electronic apparatus includes a case, pen, and antenna. The case includes an input surface and a peripheral edge having an engagement aperture opened in a direction along the input surface. The pen is used for an input operation with respect to the input surface. The pen includes an insertion piece which is made of synthetic resin and is attachably and detachably engaged in the engagement aperture while the pen is arranged against to the peripheral edge. The antenna is disposed inside the peripheral edge to be adjacent to the insertion piece in a distance which is less than the size of the insertion piece in a transverse direction of the input surface.