The present invention provides an adhesive for floor structure that can provide a floor structure inhibiting floor squeaks or joint gaps from occurring and that enables a floor finishing material to be peeled easily from a sub-floor material when repairing the floor finishing material.The adhesive for floor structure of the present invention contains a hydrolyzable silyl group-containing polyoxypropylene-based polymer (I), calcium carbonate, and a hollow filler. The adhesive for floor structure of the present invention can be used for adhesively integrating a floor finishing material 20 with a sub-floor material 30 laid on a floor base 1.