  We study a factorization of bounded linear maps from an operator space $A$ to
its dual space $A^*$. It is shown that $T : A \longrightarrow A^*$ factors
through a pair of a column Hilbert spaces $\mathcal{H}_c$ and its dual space if
and only if $T$ is a bounded linear form on $A \otimes A$ by the canonical
identification equipped with a numerical radius type Haagerup norm. As a
consequence, we characterize a bounded linear map from a Banach space to its
dual space, which factors through a pair of Hilbert spaces.
