  We propose a limit-cycle scenario of star formation history for any
morphological type of spiral galaxies. It is known observationally that the
early-type spiral sample has a wider range of the present star formation rate
(SFR) than the late-type sample. This tendency is understood in the framework
of the limit-cycle model of the interstellar medium (ISM), in which the SFR
cyclically changes in accordance with the temporal variation of the mass
fraction of the three ISM components. When the limit-cycle model of the ISM is
applied, the amplitude of variation of the SFR is expected to change with the
supernova (SN) rate. Observational evidence indicates that the early-type
spiral galaxies show smaller rates of present SN than late-type ones. Combining
this evidence with the limit-cycle model of the ISM, we predict that the
early-type spiral galaxies show larger amplitudes in their SFR variation than
the late-types. Indeed, this prediction is consistent with the observed wider
range of the SFR in the early-type sample than in the late-type sample. Thus,
in the framework of the limit-cycle model of the ISM, we are able to interpret
the difference in the amplitude of SFR variation among the morphological
classes of spiral galaxies.
