Currently social network games with an emphasis on the relationship between the friends, especially women users and the elderly users of over forties, have contributed to the expansion of game market attracting large audiences. Though recent interest in social network games and the explosive propagation of social network game into game industry, scholarly research for social network game is insufficient. The objective of the study is to explore the success factors for successful social network games through the depth interview with game experts. We suggest the guidelines for development of social network game. Commercial success of social network games and the number of users with the best game, farmville, were investigated for understanding key success factors in social network game field. As a result, social interaction, simple interface, asynchronous method, instrumental rationality factors have been identified. This result of the study will expect the guideline in order to develop a successful social network games.