The CALET Calorimeter on the International Space Station(ISS) has previously measured the
flux and spectrum of iron cosmic-ray nuclei above 10 GeV/n. In order to extend the measurement
to the region below 10 GeV/n, we carry out an analysis to utilize the geomagnetic effect. Cutoff
rigidities of cosmic-ray nuclei are calculated for all directions for each observation point in the
ISS orbit. The integral spectrum of observed rigidities is then obtained by counting the number
of iron nuclei in each bin of cutoff rigidity. The absolute flux and differential spectrum are then
calculated by taking the detection efficiencies into account. Here we present the details of the
analysis procedure and the iron spectrum below 10 GeV/n.