A determination device stores a plurality of pieces of reference data associated with a predetermined movement pattern of a controller, and determines whether or not output values that respectively have a given relationship with reference data have been output from an acceleration sensor in a predetermined order within an input reception period in which an input that moves the controller in the predetermined movement pattern is received. The determination device receives an input that moves the controller in the predetermined movement pattern and performs a game process when the determination device has determined that the output values that respectively have the given relationship with the reference data have been output from the acceleration sensor in the predetermined order within the input reception period.