A portable sound device comprising: a main body having an earbud holder; an earbud detachably mounted in the earbud holder, the earbud configured to output sound; a main board located in the main body, the main body being connected to the earbud via a sound cable; and a rotary module mounted in the main body, the rotary module being configured to be rotated to wind or unwind the sound cable, the rotary module including: a shaft fixed to the main body; a bobbin rotatable about the shaft, the sound cable being windable or unwindable around an outer circumferential surface of the bobbin; a reel spring configured to provide a rotary force to the bobbin; a track having a concave part, the track being rotated with the bobbin when the bobbin is rotated; a guide plate having a guide slot through which the shaft extends, the guide slot extending in a first direction; a bump protruding from the guide plate, the bump being inserted into the track, wherein the bump is moved along the track when the bobbin is rotated; and a bracket fixed to the main body to cover the guide plate, the bracket including a stopper slot extending in a direction parallel to the first direction in which the guide slot extends, and wherein the guide plate includes a stopper boss configured to be inserted into the stopper slot. a main body having an earbud holder; an earbud detachably mounted in the earbud holder, the earbud configured to output sound; a main board located in the main body, the main body being connected to the earbud via a sound cable; and a rotary module mounted in the main body, the rotary module being configured to be rotated to wind or unwind the sound cable, the rotary module including: a shaft fixed to the main body; a bobbin rotatable about the shaft, the sound cable being windable or unwindable around an outer circumferential surface of the bobbin; a reel spring configured to provide a rotary force to the bobbin; a track having a concave part, the track being rotated with the bobbin when the bobbin is rotated; a guide plate having a guide slot through which the shaft extends, the guide slot extending in a first direction; a bump protruding from the guide plate, the bump being inserted into the track, wherein the bump is moved along the track when the bobbin is rotated; and a bracket fixed to the main body to cover the guide plate, the bracket including a stopper slot extending in a direction parallel to the first direction in which the guide slot extends, and a shaft fixed to the main body; a bobbin rotatable about the shaft, the sound cable being windable or unwindable around an outer circumferential surface of the bobbin; a reel spring configured to provide a rotary force to the bobbin; a track having a concave part, the track being rotated with the bobbin when the bobbin is rotated; a guide plate having a guide slot through which the shaft extends, the guide slot extending in a first direction; a bump protruding from the guide plate, the bump being inserted into the track, wherein the bump is moved along the track when the bobbin is rotated; and a bracket fixed to the main body to cover the guide plate, the bracket including a stopper slot extending in a direction parallel to the first direction in which the guide slot extends, and