There is provided a load collapse prevention device including a pair of holders (5) fixedly attached to parts of the inner wall of a vehicle compartment, at both ends thereof, in a vehicle-width direction, on the side of the ceiling, respectively, so as to opposite to each other, each having a stopper for engaging a joint, wherein the holders (5) each have a lead-in part (11A, 11B), formed by notching parts of the side faces and lower face of the holder, forming a guide groove wide width part (14), and a guide groove (10) continuing from the lead-in parts (11A, 11B) to the stopper, thereby introducing a stay (2) from the lower part of the holders into the guide groove (10) while the joint is in as-retracted state, then guiding the stay (2) to the stopper. As a result, with load collapse prevention device, the joints can be fitted to the holders, respectively, by one-handed operation, and the respective joints on the right and left sides can be concurrently and easily fitted to the respective holders (5).