Disclosed is a game system comprising a monitor (3) that outputs the game screen display, a touch panel (5), and an external memory device (20) that stores sequence data (28) which records the operation timing for touch operation of a touch panel (5). Furthermore, the game system displays objects (60) corresponding to each operation timing within the predetermined time range on a game screen (50) and displays a judgment line (65) that corresponds to the current time and moves within the game screen (50), such that the judgment line (65) traverses in order each object (60) at the operation timing recorded in the sequence data (28). The game system also alters at least either the judgment line (65) movement direction or movement speed according to predetermined conditions.