  In this article, we consider the connection problem of the KZ
(Knizhnik-Zamolodchikov) equation on the moduli space $\cM_{0,5}$, and show
that the connection matrices are expressed in terms of the Drinfel'd
associator. As the compatibility condition on the connection problem, we have
the pentagon relation for the Drinfeld associators. As an application of the
connection problem, we derive the five term relation for dilogarithms.
