  We have performed a detailed V/Vmax test for a sample of the Canada-France
Redshift Survey (CFRS) for the purpose of examining whether the comoving number
density of field galaxies changes significantly at redshifts of z<1. Taking
into account the luminosity evolution of galaxies which depends on their
morphological type through different history of star formation, we obtain
<V/Vmax> \sim 0.5 in the range of 0.3<z<0.8, where reliable redshifts were
secured by spectroscopy of either absorption or emission lines for the CFRS
sample. This indicates that a picture of mild evolution of field galaxies
without significant mergers is consistent with the CFRS data. Early-type
galaxies, selected by their (V-I)_{AB} color, become unnaturally deficient in
number at z>0.8 due to the selection bias, thereby causing a fictitious
decrease of <V/Vmax>. We therefore conclude that a reasonable choice of upper
bound of redshift z \sim 0.8 in the V/Vmax test saves the picture of passive
evolution for field ellipticals in the CFRS sample, which was rejected by
Kauffman, Charlot, & White (1996) without confining the redshift range.
However, about 10% of the CFRS sample consists of galaxies having colors much
bluer than predicted for irregular galaxies, and their \avmax is significantly
larger than 0.5. We discuss this population of extremely blue galaxies in terms
of starburst that has just turned on at their observed redshifts.
