  Effect of the tensor force on $\beta$?-decay is studied in the framework of
the proton-neutron random-phase-approximation (RPA) with the Skyrme force. The
investigation is performed for even-even semi-magic and magic nuclei,
$^{34}$Si, $^{68}$, $^{78}$Ni and $^{132}$Sn. The tensor correlation induces
strong impact on low-lying Gamow-Teller state. In particular, it improves the
?$\beta$-decay half-lives. $Q$ and $ft$ values are also investigated and
compared with experimental data.
