This paper proposes a frequency tuning method of the piezoelectric sound absorbing panel. The piezoelectric elements on the panel shunted with an inductance and a resistance work like a dynamic vibration absorber. The sound absorbing panel transforms sound energy into the vibration energy, and this vibration energy is dissipated through the resistance using electrical resonance. Because the piezoelectric sound absorbing panel has high sound absorption coefficient around its natural frequency, this method can be used for low-frequency noise reduction. However, the frequency at which the sound absorption coefficient becomes 1 was automatically determined in the method proposed in the previous research. Therefore, this paper proposes the frequency tuning method of the piezoelectric sound absorbing panel using the LR circuit. The governing equations were theoretically derived, and the optimum values of the LR circuit were formulated. Theoretical analysis was validated through simulations and experiments.