The present invention presents a piezoelectric piece for a piezoelectric vibrator and a manufacturing method thereof. The piezoelectric piece for a piezoelectric vibrator in accordance with an embodiment of the present invention includes: a base; and a vibrating arm connected to the base and having a groove formed therein. Here, one surface inside the groove includes: a first slope extended from an upper portion of the groove in a lower direction so as to have a first angle; and a second slope extended from a lower portion of the first slope in a lower direction so as to have a second angle that is greater than the first angle, and a rate of a depth of the first slope for a depth of the groove is greater than or equal to 0.5 and less than or equal to 1.