A sound processing apparatus includes a sound processing section configured to produce left and right channel effect signals by conducting a sound process on left and right channel sound signals, a sound image area expanding section configured to produce left and right channel sound image signals by which sound images are localized outside left and right 2-channel speakers, and a signal combining section configured to add the left channel sound signal and the left channel sound image signal, and add the right channel sound signal and the right channel sound image signal.