  Based on a simple model of a layered superconductor with strong attractive
interaction, we find that the separation of the pair-condensation temperature
from the pair-formation temperature becomes more remarkable as the interlayer
hopping gets smaller. We propose from this result the BCS-BEC crossover induced
by the change in dimensionality, for instance, due to insertion of additional
insulating layers or application of uniaxial pressure. The emergence of a
pseudogap in the electronic density of states, which supports the idea of the
dimensionality-induced BCS-BEC crossover, is also verified.
