In this article, we present a ceiling-mounted mobile robot, HanGrawler, with high-speed mobility and the ability to freely select and adjust its route under a ceiling plate. HanGrawler hangs from the holes of a perforated metal ceiling plate using newly developed mechanically constrained hanging mechanisms mounted on crawler-type traveling equipment. These mechanisms continuously grasp the ceiling holes while moving in a straight line. Specially designed turntables are installed at certain ceiling points to change the HanGrawler movement direction to facilitate two-dimensional motion. A performance evaluation experiment confirms that HanGrawler can travel linearly at 0.1 m/s, turn at an 8.5°/s rotational speed, and carry a maximum load of 60 kg. The experiment also reveals that HanGrawler can carry a heavy load only when the timings of the hanging mechanism hooking motions and turntable rotational speed are tuned. This transport system can be utilized not only for part transportation on production lines but also for logistics in general.