  We report discovery of actively star forming elliptical galaxies in a
morphologically classified sample of bright galaxies at a low redshift obtained
from the Sloan Digital Sky Survey. The emission lines of these galaxies do not
show the characteristics of active galactic nuclei, and thus their strong
H$\alpha$ emission is ascribed to star formation with a rate nearly as high as
that is seen in typical late spiral galaxies. This is taken as evidence against
the traditional view that all elliptical galaxies formed early and now evolve
only passively. The frequency of such star forming elliptical galaxies is a few
tenths of a percent in the sample, but increases to 3% if we include active S0
galaxies. We may identify these galaxies as probable progenitors of so-called
E+A galaxies that show the strong Balmer absorption feature of A stars
superimposed on an old star population. The approximate match of the abundance
of active elliptical plus S0 galaxies with that of E+A galaxies indicates that
the duration of such late star formation episodes is of the order of $\gsim 1$
Gyr. If we interpret these galaxies as new additions to the early-type galaxy
population, and if we assume a power law for their number evolution, the
abundance of early-type galaxies at $z=1$ is about 30% less than that at $z=0$.
