Provided is a base isolation floor structure containing a base isolation frame containing plural frames, and plural base isolation bearings that support the base isolation frame, in which the base isolation bearing contains a base isolation structure that has plural rolling member and is disposed horizontally movably freely on a floor surface, a connecting member that is disposed above the base isolation structure and is connected to the base isolation frame, an elastic plate member that is disposed between the connecting member and the base isolation structure, and a rod member having one end thereof that extends downward and is fixed to the base isolation structure, and the other end thereof that extends upward and is inserted with an allowance into a through hole formed in the connecting member.