Understanding control mechanisms underlying adaptive animal locomotion will provide us a design scheme for robots which can behave autonomously depending on environments. To address this issue, it is important to capture the interplay between local pattern generating circuits, descending commands from higher centers, and sensory feedback. However, the essential interplay between them that generates adaptive behavior in response to the situation remains unclear. Here, we focused on centipedes and explored the interplay by observing the decision-making when they faced the edge of the precipice during walking. We found that a ventral nerve cord-transected centipede stopped walking in a shorter distance forward than the intact one. From the results, we extended our previous mathematical model for walking based on decentralized control and proposed a descending control mechanism which utilizes ground reaction forces detected at the legs for deciding whether to move forward.