  Central issues in the electronic structure of underdoped cuprate
superconductors are to clarify the shape of the Fermi surfaces and the origin
of a pseudogap. Based on the model proposed by Kamimura and Suwa which bears
important characteristics born from the interplay of Jahn-Teller Physics and
Mott Physics, we show that the feature of Fermi surfaces is the Fermi pockets
constructed by doped holes under the coexistence of a metallic state and of the
local antiferromagnetic order. Below $T_{\rm c}$ the holes on Fermi pockets
form Cooper pairs with d-wave symmetry in the nodal region. In the antinodal
region all the states below the Fermi level are occupied by electrons so that
there is no gap, not even pseudo both below and above $T_{\rm c}$. Calculated
angle-resolved photoemission spectrum below $T_{\rm c}$ show a coherent peak at
the nodal region while a broad hump in antinodal region. From this feature the
origin of the two distinct gaps in observed ARPES is elucidated. The
finite-size-effects of a spin-correlation length coexisting with a metallic
state are discussed. In particular, we discuss a possibility of the spatially
inhomogeneous distribution of Fermi-pocket-states and of
large-Fermi-surface-states above $T_{\rm c}$ which changes with time. Finally a
new phase diagram for underdoped cuprates is proposed.

Superconductivity