  We study the near-threshold $\eta '$ production mechanism in nucleon-nucleon
and $\pi N$ collisions under the assumption that sub-threshold resonance
$N^{*}(1535)$ is predominant. In an effective Lagrangian approach which gives a
reasonable description to the $pN \to pN \eta$ and $\pi p \to p \eta$
reactions, it is found that t-channel $\pi$ exchange make the dominate
contribution to the $pN \to pN \eta '$ process, and a value of 6.5 for the
ratio of $\sigma (pn \to pn \eta ')$ to $\sigma (pp \to pp \eta ')$ is
predicted. A strong coupling strength of $N^{*}(1535)$ to $\eta ' N$ ($g_{\eta
' NN^*}^2 /4\pi = 1.1$) is extracted from a combined analysis to $pp \to pp
\eta '$ and $\pi N \to N \eta '$, and the possible implication to the intrinsic
component of $N^{*}(1535)$ is explored.
