eh? all variants of the Vitz SCP10 have timing chains, not belts. Are you sure your car is a Vitz?
If you mean the pattern of the serpentine accessory drive belt, you need to figure out what your engine is; if it's the 1 liter, then it's a 1SZ-FE, if it's the 1.3 then most probably 2NZ-FE, I have to see one with a 2SZ-FE.