Abstract: A manhole cover locking apparatus that can promptly release the pressure in a sewerage pipe, suppress the lifting height of the cover, and stabilize the cover when lifted by pressure, including a lock main body, a hook, an engagement part that engages a claw for opening the cover; and a hook receiver on a receiving frame. The lock main body is attached rotabably about a pivotal support, and has a pressing part on a peripheral side of the cover with respect to the pivotal support part. A claw abutment surface that abuts against the claw is formed on an upper surface of the pressing part. When the hook and the hook receiver engage with each other, the claw abutment surface and an upper surface of the receiving frame are located at substantially the same height.