The invention discloses a bistable piezoelectric cantilever beam vibrator device, which consists of a pedestal, piezoelectric ceramic, an elastic substrate, an electrode, a mass block and a pair of permanent magnets, wherein the piezoelectric ceramic is adhered to the elastic substrate; the electrode is plated on the piezoelectric ceramic; the mass block and a first permanent magnet are fixed at the free end of the elastic substrate; a second permanent magnet is arranged at a position, corresponding to the first permanent magnet, on the pedestal; and the first and second permanent magnets arearranged in a way that the same polarities are opposite. In the device provided by the invention, a piezoelectric cantilever beam vibrator can form a nonlinear bistable system by utilizing a nonlinear repulsive force between the permanent magnets, and can produce stochastic resonance phenomena under certain conditions to remarkably improve piezoelectric vibration generation efficiency in a broadband low-frequency vibration environment; and the device is particularly suitable for highly-efficiently capturing broadband, low-frequency and low-amplitude vibration energy.