Device for warning dislocation of well lid

The invention relates to a device for warning the dislocation of a well lid. The device comprises a first warning device 10 and a second warning device 10, wherein the first warning device comprises a spring case 3, a steel piece 4, a spring case fastener 5, a spring 6 and a first warning ball 7; a transverse penetrating hole is formed in the first warning ball 7 and a locking hole is formed in a position at the upper part of the spring case 3; and the second warning device 20 comprises a plurality of rubber bands 11, a plurality of second warning balls 12 and a container 13 for receiving the plurality of second warning balls. The device is simple in structure and high in reliability; the existing well lid does not need to be modified; besides, the device is capable of warning the dislocation of either the submersed well lid or the non-submersed well lid, and low in cost.