A sales support method and. a sales support system which can reduce time and effort of a customer due to age verification when sales of age-restricted merchandise are performed. Age estimation information that is information obtained by estimating an age of a customer by using biometric information obtained by observing the customer is acquired, information that is input by the customer is acquired as age information of the customer in a case where the age estimation information is greater than or equal to a second predetermined age, and information based on a medium that the customer possesses is acquired as the age information of the customer in a case where the age estimation information is less than the second predetermined age, and whether the customer is older than or equal to a first predetermined age or under the first predetermined age is determined based on the age information of the customer and the determination result is notified.