To provide a connection mechanism of a simple and sure temporary set floor panel generating no step difference and separation.

An upper side engaging member 27 is attached to an upper side attaching part 23 projected on the frame side 22a of one floor panel 21, and a lower side engaging member 29 is attached to a lower side attaching part 24 projected on the frame side 22b of the other floor panel 21. The engaging members 27, 29 are mutually slid, inclining faces 27a, 29a in which force generates in the direction of mutually attracting are possessed, and connection is mutually performed by simply mounting the upper side engaging member 27.