To provide a portable sound output device capable of outputting sounds by a simple operation.

In a portable-size casing body 10, an operation switch 121, by which four kinds of chords can be assigned, and a display 11 simultaneously serving as a touch sensor panel are formed. A memory card 20 stores a sound data file for outputting sounds having sound characteristics played by an actual musical instrument and a chord data file expressing a combination of sounds. In the display 11, six string images functioning as touch sensors are displayed. A chord is designated with the operation switch 121, and a sound based on the chord is set in each string image. When the chord is designated with the operation switch 121 and the string images are touched, the sound output device makes a sound output mechanism output sounds assigned to the string images by the chord.