The present invention provides an acoustic device including a frame, a vibration system and a magnetic system. The vibration system includes a diaphragm, a voice coil assembly, and a support assembly. The support assembly includes a flexible circuit board and a support membrane. The flexible circuit board includes a first fixing end secured to the frame, a second fixing end secured to the voice coil assembly, a connecting portion, and a soldering pad. The voice coil assembly includes a first voice coil and a second voice coil. The first voice coil includes a first leading wire. The first leading wire has a first extension part extending from a surface of the first voice coil, a second extension part bending and extending from the first extension part along an outer surface of the second voice coil, and a soldering part welding to the soldering pad.