  We study the false vacuum decay of a single scalar field $\phi$ coupled to
gravity described by the Coleman-de Luccia (CdL) instanton. We show that it is
possible to numerically calculate the bounce factor, which is related to the
CdL tunneling rate, without using the thin-wall approximation. In this paper,
we consider $1/\cosh(\phi)$- and $\cos(\phi)$-type potential as examples, which
have cosmological and phenomenological applications. Especially, in the
$\cos(\phi)$-type potential we show that the range of values in which axion
decay constant can take is restricted by the form of the periodic potential if
the CdL tunneling occurs.
