To provide a lid engaging mechanism for a compact where a pressurizing operation is made to be light and a pressing member is moved back and restored reliably and smoothly by improving the shape of an elastic member.

A case body A is provided with: an engaging projecting part which engages with the engaging piece 29 of a lid B; an inclined surface which engages with a lid engaging member C; and a guide hole. The lid engaging member C is provided with a pressing plate 35, a side plate, and a sliding plate 37 connected with the lower part of the pressing plate 35. On the rear surface of the pressing plate 35, an operation piece 39 which engages with the inclined surface of the case main body A and disengages the engaging projecting part of the case body A and the engaging piece 29 of the lid B from each other is provided. At the tip of the sliding plate 37, the elastic member which is formed so as to be extended curved circularly from a prescribed position toward the center and to make the center project from the tip of the sliding plate 37 and which is inserted into the guide hole of the case body A is arranged.