In a data processor for processing pieces of input data successively sampled, a memory unit and a plurality of data transferring units for transferring data are provided. Each of the plurality of data transferring units has an upper limit number of data items successively transferable when activated. An activating unit is provided. The activating unit is configured to successively activate, within a predetermined time frame, the data transferring units without all of the data transferring units being deactivated within the predetermined time frame to thereby successively transfer the pieces of input data to the memory unit so as to store the pieces of input data therein.