  Star formation rate (SFR) is a fundamental parameter for describing galaxies
and inferring their evolutionary course. HII regions yield the best measure of
instantaneous SFR in galaxies, although the derived SFR can have large
uncertainties depending on tracers and assumptions. We present an SFR
calibration for the entire molecular gas disk of the nearby Seyfert galaxy NGC
1068, based on our new high-sensitivity ALMA 100GHz continuum data at 55pc
(=0."8) resolution in combination with the HST Pa{\alpha} line data. In this
calibration, we account for the spatial variations of dust extinction, electron
temperature of HII regions, AGN contamination, and diffuse ionized gas (DIG)
based on publicly available multi-wavelength data. Especially, given the
extended nature and the possible non-negligible contribution to the total SFR,
a careful consideration of DIG is essential. With a cross-calibration between
two corrected ionized gas tracers (free-free continuum&Pa{\alpha}), the total
SFR of the NGC 1068 disk is estimated to be 3.2\pm0.5 Msol/yr, one-third of the
SFR without accounting for DIG (9.1\pm1.4 Msol/yr). We confirmed high SFR
around the southern bar-end and the corotation radius, which is consistent with
the previous SFR measurements. In addition, our total SFR exceeds the total SFR
based on 8{\mu}m dust emission by a factor of 1.5. We attribute this
discrepancy to the differences in the young stars at different stages of
evolution traced by each tracer and their respective timescales. This study
provides an example to address the various uncertainties in conventional SFR
measurements and their potential to lead to significant SFR miscalculations.
