To provide a portable input/output unit which can easily supply the electric power without using a battery nor a wire.

When a portable input/output unit 10 is shaken in response to the input and output, the rotary shaft 22a of a power generator 22 connected to a weight 20 revolves to generate the electric power. The generated electric power is once stored in an accumulator. Then the stored electric power is controlled at a constant voltage level by a voltage stabilization circuit and supplied to a control substrate 16. The substrate 16 transfers the data to an external data processing mechanism via an infrared data sending/receiving mechanism 14 by the supplied electric power and based on the information that is inputted via a pointing device 12.