  We have measured out-of-plane resistivity $\rho_c$ for
La$_{2-x}$Sr$_{x}$CuO$_{4}$ under anisotropic pressure. c-axis compression,
which decreases $\rho_c$, reduces $T_{\rm c}$ drastically, whereas c-axis
extention, which increases $\rho_c$, enhances $T_{\rm c}$ from 38K at ambient
pressure to 51.6K at 8GPa. We find that the variation of $T_{\rm c}$ scales as
a function of $\rho_c$, and that the c-axis pressure coefficient is much
stronger than the ab-axis one. These imply that $T_{\rm c}$ depends primarily
on the interlayer, rather than the in-plane, lattice parameter.
