The present invention addresses the problem of providing a floor slab waterproof structure which exhibits excellent interlayer adhesion between a urethane waterproof material layer and an asphalt pavement layer. The present invention provides a floor slab waterproof structure which is characterized by being obtained by sequentially laminating a floor slab layer (i), a urethane waterproof material layer (ii), a urethane primer layer (iii), a bonding layer (iv) which is obtained by curing a radically curable composition, and an asphalt pavement layer (v). This floor slab waterproof structure has excellent interlayer adhesion between the urethane waterproof material layer and the asphalt pavement layer. Since this floor slab waterproof structure uses a radically curable composition which has excellent drying properties at room temperature for the bonding layer, installation time of this floor slab waterproof structure is able to be reduced.