  We constructed a model of infrared and sub-mm (hereafter IR) galaxy number
count and estimated history of the IR luminosity density. We treat the
evolutionary change of galaxy luminosities as a stepwise nonparametric form, in
order to explore the most suitable evolutionary history which reproduces the
present observational results. We found the evolutionary patterns which satisfy
both constraints required from Cosmic Infrared Background (CIRB) and IR galaxy
number counts. One order of magnitude increase of luminosity at redshift
$z=0.75 - 1.0$ was found in IR $60 \mu$m luminosity density evolution. We also
found that a large number of galaxies ($\sim 10^7$ in the whole sky) will be
detected in all-sky survey at far-infrared by Infrared Imaging Surveyor (IRIS);
Japanese infrared satellite project Astro-F.
