A music playback unit corrects the frequency characteristics of a speaker installed in a portable telephone, without using an equalizer. The musical score data is stored in a first memory, and data for correcting the velocity of musical score data for each velocity of each note is stored in a second memory. The sound generator driver reads the musical score data from the first memory, and reads the correction data from the second memory, and also corrects the velocity of the musical score data by substituting the musical score data and correction data in a predetermined calculation formula. The musical score data after the velocity is corrected is played by the MIDI sound generator, amplifier and speaker.