The utility model provides a rock stratum caving height monitor device comprising a through hole between a rock stratum and the ground surface above a goaf. The rock stratum caving height monitor device is characterized in that a plurality of galvanical wires are arranged in the through hole at intervals. Two ends of each galvanical wire are lead to the ground surface and connected with an indicating monitor. The rock stratum caving height above the goaf can be gained duly and accurately, so that corresponding protective measures can be made. Rock burst produced by the caving can be avoided effectively and safety production hidden dangers in a mine can be eliminated. According to the rock stratum caving height monitor device, a complete early warning mechanism is formed, and meanwhile the early warning accuracy is also improved, so that the safety production in the mine is guaranteed.