A diaper alarm device, comprises a shell, a circuit board mounted in the shell, and a connection mechanism configured to detachably connect a diaper sensor, wherein the shell comprises a plate body with a receiving cavity, a main cover with a downward concave arc surface on one end, and a slave cover with a cam surface on one end. A mouth portion of the receiving cavity is arranged on one plate surface of the plate body. The main cover and the slave cover are arranged on the mouth portion of the receiving cavity side by side. In addition, the cam surface is in sliding contact with the concave arc surface. A chute in which a metal shaft is mounted is formed in the bottom of the slave cover. Two ends of the metal shaft, which are bent, are then pin-connected to the plate body or the circuit board, such that the slave cover is limited in the mouth portion of the receiving cavity and cannot rotate until suffering an external force. The connection mechanism comprises connection electrodes arranged on the circuit board, and a plurality of short pins arranged on the lower surface of the slave cover, wherein the connection electrodes are located below the slave cover and correspond to the plurality of short pins, such that the diaper sensor and the diaper alarm device can be detachably connected conveniently, rapidly and reliably.
