The invention discloses an inertial sensor device, which is used to be connected with a hand-held electronic device. The inertial sensor device comprises an accelerometer unit, a gyroscope unit and aconnector module, wherein the accelerometer unit is used for generating acceleration sensing signals corresponding to X, Y and Z directions; the gyroscope unit is used for generating angular acceleration sensing signals corresponding to X, Y and Z axes; the connector module is provided with a plug used to be plugged in a joint connector of the hand-held electronic device. The inertial sensor device is conveniently connected and disconnected with the hand-held electronic device, so that a user can use body motions to control a special cursor on an electronic game picture or a graphical user interface.