  We have studied the spin-Peierls (SP) transition in alpha'-Na_{1-delta}V_2O_5
(delta = 0, 0.01 and 0.1) by means of Raman scattering. At room temperature, we
observe six A_1 and three A_2 phonon modes and a broad Raman band. Below
T_{SP}several new peaks and a new broad band appear. The new peak at 62 cm^{-1}
originates from the SP-gap excitation. The new peak at 128 cm^{-1} and the new
broad band between 130 and 400 cm^{-1} come from two magnetic excitations. The
new peaks at 102, 646 and 944 cm^{-1} are assigned to the folded phonon modes
and their Na^+-ion deficiency dependence shows that the defect of Na^+ ion
suppresses the SPtransition. The polarized Raman spectra below T_{SP} suggest
that the possible crystal symmetry is C_s^2(Pn) or C_1^1(P1). The asymmetric
lineshape of the 531-cm^{-1} peak superimposed on the electronic Raman band
from the d-d transition around 600 cm^{-1} is interpreted in terms of the Fano
resonance between the electronic continuous band and the phonon with a finite
lifetime. The defects of the Na^+ ions reduce the Fano effect because the life
time of the phonon and the phonon-continuum interaction are decreased.
