PROBLEM TO BE SOLVED: To obtain a beam floor joining structure that enables an equipment material to be laid along an undersurface of a concrete slab, without forming an equipment opening in a wooden beam.SOLUTION: A beam floor joining structure 10 includes: a wooden beam 12; a concrete slab 30 that is supported by the wooden beam 12; and a protrusion 32 that serves as a concrete support provided between a top surface 12U of the wooden beam 12 and an undersurface 30L of the concrete slab 30.