A motion sensing device includes a housing defining a chamber that includes a number of sidewalls. A number of movable members are connected to the sidewalls and able to move toward the sidewalls. Each movable member includes a number of conductive grooves opposing the sidewalls and having a resistance layer. A number of conductive spring members are respectively fixed to the sidewalls and each include a free end movably received in one conductive groove. An inertial weight is movably received in a space defined by the movable members. When the motion sensing device is jerked, the inertial weight moves and is able to apply a pushing force to one of the movable members, causing one of the movable members to move and causing two of the free ends in the same conductive groove to move toward each other.