  We investigate the one pion decay of the Roper resonance
$N^*(1440)$$\to$$N$${\pi}$ in the Sakai-Sugimoto model of the holographic QCD.
The nucleon and Roper resonance emerge as ground and first excited states of
the collective radial motion of the instanton in the four dimensional space
with one extra dimension. It is found that the ratio of the ${\pi}$$NN^*$ and
${\pi}$$NN$ couplings, and hence the ratio of $g_A^{NN^*}$ and $g_A^{NN}$, is
well reproduced in comparison with the experimental data. The mechanism of this
result is due to the collective nature of excitations, which is very different
from that of the single particle nature of the constituent quark model. Our
results are obtained in the large-$N_c$ and large ${\lambda}$ ('t~Hooft
coupling) limit which are useful to test how baryon resonances share what are
expected in these limits.
