  The collapse of a massless scalar field in the Brans-Dicke theory of
gravitation is studied in the analysis of both analytical solution and
numerical one. By conformally transforming the Roberts's solution into the
Brans-Dicke frame, we find for $\omega > -3/2$ that a continuous
self-similarity continues and that the critical exponent does depend on
$\omega$. By conformally transforming the Choptuik's solution into the
Brans-Dicke frame, we find for $\omega > -3/2$ that at the critical solution
shows discrete self-similarity, however, the critical exponent depends strongly
on $\omega$ while the echoing parameter weakly on it.
