General tunnel lining concrete (TLC) constructed with New Austrian Tunneling Method (NATM) is an arch-shaped concrete structure without reinforcement (except for the tunnel exit). TLC is constructed using cast-in-place concrete, and it is hard to upward-cast the fresh-concrete into the tunnel ceiling. Ceiling voids caused from the bleeding water and insufficient concrete construction are occasionally observed. Arch-shaped structures having sufficient thickness indicate higher resistance to external force than other structures such as slab and wall. TLC with ceiling voids must have low ductility to the external force, so it may be collapsed by unexpected load e.g. quakes. The present study aimed to compare the load-carrying capacities of TLC models which were made with sufficient / insufficient concrete thick. In particular, the experimental study examined the strengthening effect of near-surface-mounted (NSM) technique with carbon-fiber composite cables (CFCC) for the TLC models. The previous investigation [1] reported that the upper concrete was crushed at the ultimate load even in the test of full-thick TLC model. Compared to the test results, the experiment of TLC of insufficient thickness indicated lower load capacity. However, it was confirmed that the NSM-CFCC strengthened TLC member including the ceiling void of 20 mm thick indicated equivalent load capacity to the full-thick TLC model.