A network synchronizing system includes plural apparatuses. A first apparatus includes a first recording unit to record personal data of one or more users who can use the first apparatus to share the personal data with other apparatuses. A second apparatus includes a first setting unit to record personal data of one or more users who can use the second apparatus; and a first control unit to compare the personal data recorded in the first setting unit and the first recording unit and update the personal data recorded in the first setting unit of the second apparatus with the latest personal data for each user. The first control unit determines that users are the same user when data uniquely provided for the users in the personal data recorded in the first setting unit and the first recording unit are the same.