- Inside the music box, there is a mechanism called the "musical movement" that creates the music. The musical movement is made up of several parts. At the bottom of the music box is a base plate (normally made of brass) which supports the musical movement.
- There is a steel comb with teeth of varying lengths that are tuned to achieve musical notes. This comb is set into motion by a revolving metal cylinder. It lies above the base plate adjacent to the cylinder. Generally, the more teeth on the comb, the more expensive the music box.
- The metal (usually brass) cylinder has raised bumps strategically placed on it so that when it revolves, it plucks the teeth of the comb at different intervals, creating notes. Some music boxes have interchangeable cylinders to offer the listener a variety of songs.
- Inside a brass housing is the spring mechanism which is wound up by a key on the outside of the box. The spring mechanism is attached to the cylinder and sets it in motion. The length of play is determined by how many times the key is turned.
- There is a speed governor that regulates the speed of the spring mechanism. It ensures the music will play at a regular rhythm.
- All of the parts of the musical movement are contained within a decorative box, ceramic figurine or any other number of artistic housing units. Music boxes can fit in the palm of your hand, or they can be as big as a piano.
