We show an explicit functional equation of the standard L-function associat
ed with an automorphic form on a definite orthogonal group over a totally r
eal algebraic number field. This is a completion and a generalization of ou
r previous paper, in which we constructed standard L-functions by using Ran
kin-Selberg convolution and the theory of Shintani functions under certain
technical conditions. In this article we remove these conditions. Furthermo
re we show that the L-function of f has a pole at s = m/2 if and only if f
is a constant function.