The purpose of the present invention is to provide a base fabric for an airbag and an airbag wherein the strength of sewn parts is high, pressure resistance is superior for an airbag during high-pressure deployment at high speeds, and pressure resistance can be maintained even after passage of time in heat. This base fabric for an airbag is characterized by being formed from woven polyamide fibers, and the retention of sewn part strength in the base fabric with heating before and after heat treatment for 400 hours at 140° C. being 70% or greater.