  We propose a new method to search for high-redshift galaxies that is based on
an intermediate-band dropout technique rather than the usual broad-band dropout
one. In this method, we use an intermediate-band filter whose central
wavelength is longer than 7000 \AA. This new method makes it possible to
distinguish both very late-type stars such as L and T dwarfs and dusty galaxies
at intermediate redshift from real high-$z$ Lyman break galaxies. The reason
for this is that such interlopers do not show strong intermediate-band
depression although they have very red broad-band colors that are indicative of
Lyman break galaxies. Applying our new method to imaging data sets obtained
with the Suprime-Cam on the Subaru Telescope, we find a new sample of Lyman
break galaxies at $z \simeq 5$.
