The construction of small tunnels in urban underground structures greatly affects the stability of the structures installed with anchors to secure structural stability causing many problems in the stability of structures. In order to solve such a problem, numerical analysis was carried out to investigate the anchor force, which is changed by the interference between compression or tension anchors and the underground structure. The results of this study indicate that the maximum and minimum shear force ratios of tension anchors according to the spaces are relatively higher than those of compression anchors. In addition, the results indicated that, in the case of tunneling adjacent to a structure, compression anchors installed on the base surface should secure vertical spaces not smaller than 0.5D of the minimum tunnel radius and horizontal spaces not smaller than 0.75D and tension anchors should secure both vertical and horizontal spaces not smaller than 0.5D.