PROBLEM TO BE SOLVED: To provide means for enabling the monitoring of a contact guide member at the minimum energy cost preferably without external cable connection and without remodeling a bearing box or a linear guide device in large.SOLUTION: A module 10 monitors at least one of characteristic physical amounts of the state of a bearing 80 housed in a bearing box 72. The module 10 includes at least one state sensor and an electric circuit. The at least one state sensor supplies an electrical signal for measuring the physical amounts. The electrical circuit includes a power-saving circuit which, connected to the state sensor, is connected to a reference circuit of the state sensor, a feeder circuit for a monitoring device and a displacement sensor 58 of a guide member 80. The power-saving circuit resumes the operation of the reference circuit when a characteristic physical amount of the operation of the guide member 80 measured by the displacement sensor 58 exceeds a prescribed threshold over a prescribed time.