The invention relates to a bone conduction hearing aid device, comprising an in-vitro voice processor which comprises a shell, a metal disk, an electromagnetic vibrator placed in the shell, a microphone and a circuit board, wherein a digital signal processor DSP is integrated and mounted on the circuit board. A vibrator packaging and separating cabin is arranged in the shell. A port is arranged on the right side wall of the shell. The port is communicated with the vibrator packaging and separating cabin. An output end part of the electromagnetic vibrator stretches out of the port and is connected with the metal disk. At least one microphone is arranged on the wall of the shell. The electromagnetic vibrator is arranged in the vibrator packaging and separating cabin. The port is communicated with the vibrator packaging and separating cabin. The output end part of the electromagnetic vibrator stretches out of the port and is connected with the center of the metal disk. According to the device, the electromagnetic vibrator is placed in the vibrator packaging and separating cabin. The sound propagated from the electromagnetic vibrator to the microphone is reduced and attenuated, so the sound propagated form the electromagnetic vibrator to the microphone is reduced or attenuated, and the howling of the bone conduction hearing aid device is greatly weakened.