Do I pay an auto insurance deductible if I cause the accident, or does the owner of the other car pay?

I scratched someone's car and the cost is going to be less than my deductible
So I don't pay a deductible for property damage, but I do for damage to the car? Who pays the deductible? That's my question!!!

Your deductible is for damage to your car, not his. If the damage is less than HIS deductible, you pay for the damage. You can let your insurance company pay, but it is normally more cost-effective in the long run to just pay it. It saves having an accident on your insurance record. If the damage is greater than HIS deductible, and he files a claim, His insurance company will sue you and your insurance company for the full amount. Your company ends up paying, you have an at-fault accident on your record, lose eligibility for no-claims discount for up to 5 years, and possibly have a surcharge on your premium.