A movement measuring device determines the speed of the body's specific movement on the basis of the maximum value of the acceleration sensed by an acceleration sensing unit attached to the body, when the body has made a specific movement. For example, when the player wears the device on his arm and makes a punching motion, the punching speed is found from the maximum acceleration resulting from the punching action. Furthermore, a game device obtains data indicating the magnitude of a specific movement of the body, on the basis of the acceleration sensed by an acceleration sensing unit, and then decides the outcome of the game on the basis of the strength and weakness of the punch. This enables the user to easily play a fighting sport game involving the player's actual punching motions anywhere.