Provided is a data generation system which can mitigate burden on generation of sequence data, and which is capable of suppressing variation in length of periods between display start timings and operation timings in accordance with a data creator. In a data generation system (70) which, while playing a song, generates sequence data (28) used in a game in which an object (60) displayed at a display start timing within a game area (52) moves to a first operation criterion portion (55A) at an operation timing, the display start timing and the operation timing are described for the sequence data (28), and the data generation system (70) calculates an estimated number of beats that is a proper value for a period between the display start timing and the operation timing on the basis of the difficulty of the game, and next, calculates an operation timing for the display start timing on the basis of a range for a number of beats relative to the calculated estimated number of beats, and afterwards, generates sequence data on the basis of the display start timing and the operation timing.