An inventive structure of the reduction device of the spring driving musical movement comprises a musical movement base, a gear fixed base, a step spur gear, a bilateral gear and a friction unit; wherein the gear fixed base, formed from project plastic material, installs with a locating hole, two parallel concave grooves and a right-side bilateral gear installing groove thereon; and rivets with the musical movement base in a fixed position by the locating hole. After said step spur gear separately parallelizes in said parallel concave groove, said right-side bilateral gear installing groove and a left-side bilateral gear installing groove on the musical movement base were separately installed with a bilateral gear. And said friction unit locates on the musical movement base to make a worm thereon mutually and vertically engages with a left-side gear of the bilateral gear, to become a spring driving musical movement reduction device.