This paper focuses on the development of a spring-suspended suction cup with buckled plate spring. The proposed idea is that the buckled plate spring is used for adjusting negative pressure of suction cup. Moreover, the stored elastic energy in the plate-spring compensates pressure loss when air inflow happens in the suction cup. Existing passive suction cups are difficult to keep attachment to rough surfaces, where there exists air inflow, however, the proposed idea is able to continue attachment in a small air inflow environment without any actuator or energy source. Therefore the spring-suspended suction cup is able to decrease weight, size, and energy consumption of the attachment mechanism. This paper presents calculation of attachment time of the spring-suspended suction cup, input energy needed to start attachment, and estimation of air inflow to suction cup. From numerical comparison and experimental verification, it is confirmed that the proposed idea maintains attachment force for a longer time than the volume-fixed suction cup that is commonly used.