Sound device and sound system

There is provided a sound device used while being worn on the listener's ears.The sound device includes a main body installed on a medial surface of an auricle, a holding portion having an annular hollow structure arranged to be coupled to an intertragic notch of an ear near an entrance of an ear canal, a sound guide portion formed as a pipe structure having one end communicating with the main body and another end communicating with the holding portion, an open/close operation unit configured to open or close an earhole, and a control unit configured to control driving of the open/close operation unit. The earhole open/close state is set for each user. The earhole open/close state can be switched depending on the type of application or content to be played, ambient noise level, user behavior, position information, or the like.