  We study the bispectrum of the matter density perturbations induced by the
large scale structure formation in the most general second-order scalar-tensor
theory that may possess the Vainshtein mechanism as a screening mechanism. On
the basis of the standard perturbation theory, we derive the bispectrum being
expressed by a kernel of the second order of the density perturbations. We find
that the kernel at the leading order is characterized by one parameter, which
is determined by the solutions of the linear density perturbations, the Hubble
parameter and the other function specifying nonlinear interactions. This does
not allow for varied behavior in the bispectrum of the matter density
perturbations in the most general second-order scalar-tensor theory equipped
with the Vainshtein mechanism. We exemplify the typical behavior of the
bispectrum in a kinetic gravity braiding model.
