  The braneworld scenario is studied and the effective action of 3-brane living
in 5-dim. Minkowski space is constructed. This action is proved to be invariant
under spontaneously broken scale and Weyl symmetries and to encode a model of
quadratic gravity generalizing the Starobinsky model. The symmetry breaking
generates the Hilbert-Einstein term with the Newton constant
$G_{N}\sim\frac{1}{\mu^{2}}$, where $\mu$ is a mass scale equal to the mean
curvature of the vacuum hyper-worldsheet of 3-brane. This result proposes a
brane modification of the mechanism of spontaneously generated gravity.
