To provide a substrate having a handrail that can retrofit the handrail to a wall surface where no reinforcing members are provided and can easily arranged to the length shape of the handrail to be mounted, to provide the system, and to provide a mounting method of the handrail using the system.

The handrail-mounting substrate comprises a base section 17 having an adhesive-coated surface 17a where an adhesive is coated, and a mounting section 14 that is arranged on the surface of the base section 17. A groove section 11 in the longitudinal direction is formed on the upper surface of the base section 17. A screw hole 13 is punched to the groove section 11. The system has a connecting member 30 for connecting mounting handrail-mounting substrates 10. Then, the mounting method comprises a process for applying an adhesive to the adhesive-coated surface 17a for adhering and sticking to a specific location on the wall surface where a handrail 2 should be installed, a process for inserting a screw member 13a into the screw hole 13 that is punched to the groove section 11 for fixing, and a process for mounting the handgrip 2 to the fixed mounting handrail-mounting substrate 10.