A software activation system includes a sewing machine and at least one server connected via a network. The sewing machine acquires an authentication code corresponding to an activation target software that is at least one of a program and data not activated on the sewing machine, and transmits, to an authentication server included in the at least one server, an authentication request including the acquired authentication code. The server acquires an authentication key on the basis of the authentication request, when the authentication request is received by the first receiver; and transmits the acquired authentication key to the sewing machine. The sewing machine also receives the authentication key from the authentication server, determines whether the received authentication key satisfies a predetermined authentication condition, and activates the activation target software on the sewing machine when it is determined that the authentication key satisfies the predetermined condition.