  The cross section of neutron-deuteron radiative capture $n d\to {^3H}\gamma$
is calculated at energies relevant to Big-Bang nucleosynthesis ($ 20 \leq E
\leq 200 $ Kev) with pionless Effective Field Theory. At these energies,
magnetic transition M1 gives the dominant contribution. The M1 amplitude is
calculated up to next-to-next-to leading order(N$^2$LO) with insertion of
three-body force. Results are in good agreement within few percent theoretical
uncertainty in comparison with available calculated data below E=200 Kev.
