  We examine whether the ultraluminous infrared galaxies that contain a type I
Seyfert nucleus (a type I ULIRG) are in the transition stage from ULIRGs to
quasi-stellar objects (QSOs). To inspect this issue, we compare the black hole
(BH) mass, the bulge luminosity and the far infrared luminosity among type I
ULIRGs, QSOs and elliptical galaxies. As a result, we find the following
results; (1) The type I ULIRGs have systematically smaller BH masses in spite
of the comparable bulge luminosity relative to QSOs and elliptical galaxies.
(2) The far-infrared luminosity of most type I ULIRGs is larger than the
Eddington luminosity. We show that above results do not change significantly
for 3 type I ULIRGs that we can estimate the visual extinction from the column
density. Also, for all 8 type I ULIRGs, we investigate the effect of
uncertainties of BH mass measurments and our sample bias, so that it turns out
that our results do not alter even if we consider above two effects. In
addition, Anabuki (2004) revealed that their X-ray properties are similar to
those of the narrow line Seyfert 1 galaxies. These would indicate that active
galactic nuclei (AGNs) with a high mass accretion rate exist in the type I
ULIRGs. Based on all of these findings, we conclude that it would be a natural
interpretation that type I ULIRGs are the early phase of BH growth, namely the
missing link between ULIRGs and QSOs. Moreover, by comparing our results with a
theoretical model of a coevolution scenario of a QSO BH and a galactic bulge,
we show clearly that this explanation would be valid.
