To provide an arch bridge capable of reducing the number of constituent members greatly and reducing construction cost as a whole.

In this arch bridge, an arch beam stretched between abutments in a rigidly connected state is used as a floor construction beam as it is, and a traffic floor slab is constructed on the arch beam. If a difference is generated in a vertical slope between the arch beam and a road, a light-weight structural material such as foam styrol and foam mortar is provided between the upper face of the arch beam and the traffic floor slab in the vicinity of both the abutments of the arch beam to raise both sides in forward and backward directions of the traffic floor slab and adjusts the vertical slope.