Hybrid composite glulam timber reinforced using deformed steel bars and epoxy resin adhesive (RGTSB), was significantly developed in Kagoshima University. In this paper, new experimental data on structural behaviour of CLT-to-the RGTSB composite beams is presented. Two full-scale simply-supported beams were tested under four-point flexural bending in elastic or until destructive. The beam composite sections were built up of a top flange part made of CLT slab and a web part made of RGTSB rectangular section. The CLT slab and the web part were mechanically fastened using thread self-tapping screws. Experimental parameters of the specimens are the arrangement of the steel bars in RGTSB beams, the thickness of the slab, and the spacing pitch of the screws.