The invention provides a piezoelectric vibrating plate which can prevent the vibration of the vibrating arm from being passed down to a package during the installation process; and a piezoelectric vibrator comprising the same. The piezoelectric vibrating plate is characterized by comprising a pair of vibrating arms, which are parallelly arranged in the width direction; a supporting arm, which is arranged between the vibrating arms; a base, which is used to connect the vibrating arms and the supporting arms; and an assembling part, which is arranged on the supporting arm; wherein a groove is formed between the assembling part and the base in the length direction of the supporting arms.