Let D be a finite digraph with the vertex set V (D) and the arc set A(D). A function f : $V(D){ ightarrow}{-1,;1}$ defined on the vertices of a digraph D is called a bad function if $f(N^-(v)){leq}1$ for every v in D. The weight of a bad function is $f(V(D))=sumlimits_{v{in}V(D)}f(v)$. The maximum weight of a bad function of D is the the negative decision number ${eta}_D(D)$ of D. Wang [4] studied several sharp upper bounds of this number for an undirected graph. In this paper, we study sharp upper bounds of the negative decision number ${eta}_D(D)$ of for a digraph D.