V445 Pup ( 2000 ) is a unique object identified as a helium nova .
Color indexes during the outburst are consistent with those of free-free emission .
We present a free-free emission dominated light curve model of V445 Pup on the basis of the optically thick wind theory .
Our light curve fitting shows that ( 1 ) the white dwarf ( WD ) mass is very massive ( M _ { WD } \gtrsim 1.35 ~ { } M _ { \sun } ) , and ( 2 ) a half of the accreted matter remains on the WD , both of which suggest that the increasing WD mass .
Therefore , V445 Pup is a strong candidate of Type Ia supernova progenitor .
The estimated distance to V445 Pup is now consistent with the recent observational suggestions , 3.5 \lesssim d \lesssim 6.5 kpc .
A helium star companion is consistent with the brightness of m _ { v } = 14.5 mag just before the outburst , if it is a little bit evolved hot ( \log T~ { } ( K ) \gtrsim 4.5 ) star with the mass of M _ { He } \gtrsim 0.8 ~ { } M _ { \sun } .
We then emphasize importance of observations in the near future quiescent phase after the thick circumstellar dust dissipates away , especially its color and magnitude to specify the nature of the companion star .
We have also calculated helium ignition masses for helium shell flashes against various helium accretion rates and discussed the recurrence period of helium novae .