A motion of a first unit is detected based on an output from a first acceleration sensor provided in a first unit of a controller, and a motion of a second unit is detected based on an output from a second acceleration sensor provided in a second unit separate from the first unit. A game control is performed using the detected motions. Thus, with a game apparatus using a plurality of acceleration sensors or a plurality of sensors capable of detecting a motion a dynamic play is made possible with a high degree of freedom of motion and an intuitive motion input is realized.