The utility model discloses a cable strand breakage alarm device comprising a rack and a wire distributing disc arranged on the rack. The wire distributing disc is provided with a plurality of sets of main wire dies allowing a wire to pass through. A support plate is fixed on each main wire die, the support plate is connected with a sensing sheet, and the tail end of the sensing sheet is provided with an auxiliary wire die. A spring seat is fixed on the back of the wire distributing disc. A tension spring is arranged between each sensing sheet and the spring seat. A light sensing device triggered by a broken sensing sheet is arranged beside the wire distributing disc on the rack. The cable strand breakage alarm device has the following advantages: a wire passes through the main and auxiliary wire dies, any sensing sheet having a wire to pass through is disconnected with the corresponding tension spring, the tail end of the corresponding sensing sheet is unconstrained when the wire is broken, and the tail end of the sensing sheet is thrown out due to rotation of the wire distributing disc so as to trigger the light sensing device to realize wire breakage alarm. The device has a simple structure and high reliability, can meet the wire breakage alarm function of the existing bare wire, and has an insulated wire breakage alarm function.