The present invention provides an acoustic device including a frame, a vibration system and a magnetic circuit system. The vibration system includes a diaphragm, a voice coil, a voice coil holder connecting the diaphragm and the voice coil, and a support assembly connecting the frame and the voice coil holder. The voice coil holder comprises a first fixing portion extending toward a direction of the voice coil, a second fixing portion extending toward to the support assembly, and a first connecting portion connecting the first fixing portion and the second fixing portion. The first fixing portion is mounted to the voice coil, and the second fixing portion is mounted to the support assembly. The first connecting portion provides with a reinforcing rib protruding and extending from the first fixing portion.