  The open inflation model recently proposed by Hawking and Turok is
investigated in scalar-tensor gravity context. If the dilaton-like field has no
potential, the instanton of our model is singular but has a finite action. The
Gibbons-Hawking surface term vanishes and hence, can not be used to make
$\Omega_0$ nonzero. To obtain a successful open inflation one should introduce
other matter fields or a potential for the dilaton-like fields.
