Various strengthening systems have been developed for concrete bridge structures. A typical and practical strengthening application is near-surface-mounded (NSM) technique using fiber reinforced polymer (FRP) materials. As well as such deteriorated concrete bridges, old road-tunnels are also compromised structures which should be repaired and/or strengthened. Efficient strengthening systems for tunnel lining concrete (TLC) have not been sufficiently discussed while various systems are available for other structures. The study aims at development of a strengthening system applicable for TLC. In particular, the present study focused on an NSM-FRP strengthening system which is often employed in deck-slabs and girders of bridge. Most of FRP materials used in such supra-structures are laminates and rods. It may be hard to embed FRP materials into inner surface of arched tunnels. Flexible FRP must be a favorable material for strengthening of TLC. The study focused on a carbon-fiber composite cable (CFCC) which is often used in prestressed concrete structures. The CFCC is embedded in inner surface of TLC by using a polymer cementitious mortar and epoxy resin. Fundamental loading test using mock-up TLC models was conducted to examine the strengthening effect of the proposed system. The paper reports the load-carrying capacity of the strengthened TLC models.