  We calculate the kaon semileptonic form factors using the two sets of the
PACS10 configuration, whose physical volumes are more than (10 fm)$^4$ at the
physical point. The lattice spacings are 0.063 and 0.085 fm. The configurations
were generated using the Iwasaki gauge action and $N_f=2+1$ stout-smeared
nonperturbatively $O(a)$-improved Wilson quark action. From the momentum
transfer dependence of the form factors, we evaluate the slope and curvature
for the form factors at the zero momentum transfer. Furthermore, we calculate
the phase space factor, which is used to obtain $|V_{us}|$ through the kaon
semileptonic decay. These results are compared with previous lattice results
and experimental values.
