To provide a portable telephone which copes with damage of data during communication, thereby improving speech quality.

The portable telephone performs, as types of processing performed on a received signal, base band processing, data expansion processing, digital signal processing, and digital-to-analog conversion processing. The digital signal processing includes data interpolation processing. Interpolation data for the data interpolation processing is estimated using an FIR filter and set to a middle point between two pieces of different data on a time base.