The present invention relates to a game system capable of determining use time. Any one of a plurality of props is generated by a game result generation unit according to a probability, and a storage unit is caused to record any one of the generated props, or a member management unit is caused to select, according to a consumption record and a given rule, at least one of the plurality of props to be stored into a piece of account data, and the prop recorded in the account data is transferred to the storage unit, the plurality of props each having a specified game effect; moreover, when a control unit determines that a player uses at least one prop recorded in the storage unit, a corresponding specified game effect will be generated, and the used prop is deleted from the storage unit. According to the present invention, the props having different specified game effects can be collected, and the player can freely select use time, so that the player can wait for optimal use time, the effect of continuously using the game system is achieved, and the turnover of the game system can be effectively increased.