A sensing device includes a sensing transmitting module and a sensing receiving module respectively mounted in a first housing and a second housing. And an output terminal of the sensing transmitting module and an input terminal of the sensing receiving module are provided with a sensing coil and an electromagnetic rod respectively, the first housing and the second housings are cooperated with each other, and the electromagnetic rod is inserted into the sensing coil, so that the sensing coil or the electromagnetic rod is placed in magnetic field generated by the electromagnetic rod or the sensing coil thereby generating sensing voltage. The sensing parts are formed of the sensing coil and the electromagnetic rod, which significantly reduces the amount of the copper wires in the sensing coil and the electromagnetic rod, therefore the sensing device has a smaller size, lighter weight and lower cost.