  We report the pressure dependences of the superconducting transition
temperature (T_c) in several perovskite-type Fe-based superconductors through
the resistivity measurements up to ~4 GPa. In Ca_4(Mg,Ti)_3Fe_2As_2O_y with the
highest T_c of 47 K in the present study, the T_c keeps almost constant up to
~1 GPa, and starts to decrease above it. From the comparison among several
systems, we obtained a tendency that low T_c with the longer a-axis length at
ambient pressure increases under pressure, but high T_c with the shorter a-axis
length at ambient pressure hardly increases. We also report the ^75As-NMR
results on Sr_2VFeAsO_3. NMR spectrum suggests that the magnetic ordering
occurs at low temperatures accompanied by some inhomogeneity. In the
superconducting state, we confirmed the anomaly by the occurrence of
superconductivity in the nuclear spin lattice relaxation rate 1/T_1, but the
spin fluctuations unrelated with the superconductivity are dominant. It is
conjectured that the localized V-3d moments are magnetically ordered and their
electrons do not contribute largely to the Fermi surface and the
superconductivity in Sr_2VFeAsO_3.
