To provide a portable electronic apparatus provided with a contactless data communication function wherein the directivity is extended even a little.

The portable electronic apparatus is provided with: a contactless communication section including an antenna and a transmission/reception means for carrying out contactless data communication; a case body for containing the contactless communication section; an electromagnetic reflecting plate or an electromagnetic induction plate arranged inside the case body at an angle with an antenna aperture. Even when an antenna of a reader/writer is set perpendicularly to an antenna in the portable electronic apparatus, it is possible to deliver an electromagnetic wave into the antenna aperture of the portable electronic apparatus by using the reflecting plate deposited at a tilt with respect to the antenna aperture to thereby change the direction of the electromagnetic wave.