The invention provides a floor slab bridge structure capable of enhancing that strength, with which bridge girders and concrete bridge piers are rigidly joined, effectively suppressing expansion and contraction, deflection, and distortion of the bridge girders, and synergistically enhancing the strength of connection concrete itself against the expansion and contraction, distortion, etc., and being very effective as measures for prevention of collapse of bridge against a large earthquake. Slab concrete (3) is hammer-set between sides of respective bridge girders (1), which are aligned in a bridge width direction, in a length direction of the bridge girders and connection concrete (11), in which bridge girder portions supported on bridge bottom surfaces (10) of concrete bridge piers (2) supporting the bridge girders are embedded, is additionally deposited on the bridge bottom surfaces to form a floor slab bridge structure being a rigid joining structure, in which the slab concrete and the concrete bridge piers are concrete-joined together through the connection concrete.