To provide actual joining structure for actualizing rigid and actual joint for a composite floor material while preventing an actual joint portion of composite floor material from swelling due to wax.

The composite floor material A has a wood board material 2 laminated on a woody base material 1. The composite floor material A has the actual joint portion consisting of a male tongue 3 and a female tongue 4. A wax reservoir space is provided in the upper part of the actual joint portion. On the male tongue 3, a hollow portion is formed by chamfering the face ranging from a root portion on an upper face 31 of the male tongue 3 over the woody base material 1 and the wood board material 2. A tongue upper part 41 constituting the male tongue 4 is chamfered to form a hollow portion of approximately triangular cross section corresponding to the hollow portion during actual joint. The peak of the hollow triangle is made to communicate with an abutting cavity portion 21 of the wood board material.