This paper presents a new wall-climbing robot design equipped with a linkage-type walking mechanism for unstructured vertical surface navigation. A vertical unstructured surface limits the wall-climbing performance of a robot, and hence, becomes a crucial factor that necessitates research in the field of vertical wall-climbing robots. Therefore, to respond to this problem, a wall-climbing robot based on a four-bar mechanism and repeated walking locomotion via a single actuator, was studied. This feature used a symmetric linkage design to adapt to uneven surfaces in the process of overcoming obstacles with compliant motion. Moreover, for the robot's wall surface attachment, the design mechanism employed is the flat dry adhesion method. Additionally, based on the analyses of the robot's kinematics and statics, essential design parameters were determined and used in the robot's configuration. Experimental evidence confirmed that this vertical wall climbing robot can hurdle a 10-mm step, which is 100% of the stride height and 20% of the robot's height based on linkage walking mechanism design. Consequently, with such an ability, this vertical wall-climbing robot with a linkage type design can access areas wider than what commonly designed wall-climbing machines can cover.