A piezoelectric vibration piece that can ensure good drive level characteristics and a piezoelectric vibrator, oscillator, electronic device and radio-controlled timepiece in which the piezoelectric vibration piece is used are provided. The width of the base-end side of the grooves 5 is narrower than that of the tip side of the grooves 5. The base 4 includes: a mount section 4a on the outer surface of which mount electrodes 12, 13 are formed to mount the piezoelectric vibration piece 1; and an intermediate section 4b that is connected to the mount section 4a and the pair of vibrating arms 3a, 3b so as to be positioned between the mount section 4a and the pair of vibrating arms 3a, 3b, on the outer surface of which leading electrodes 14a, 14b that connect the pair of excitation electrodes 10, 11 and the mount electrodes 12, 13 are formed. The width of the mount section 4a is wider than that of the intermediate section 4b. In step parts between the mount section 4a and the intermediate section 4b, side surfaces of the mount section 4a and side surfaces of the intermediate section 4b are connected via tilted surfaces 4c that tilt with respect to a longitudinal direction.