A tonneau cover device (1) includes a tonneau cover (42) attached to a hatchback door (45). A movable guide (49a) is arranged on the tonneau cover (42) and is guided by a fixed guide (48), which is arranged in a vehicle. The tonneau cover (42) moves to an extension position when the hatchback door closes and a storage position when the hatchback door opens. A detector (44) detects whether movement of the tonneau cover is obstructed due to contact with an object. A controller (21) moves the tonneau cover to where the movable guide can come into contact with the fixed guide in a state in which the hatchback door is open when the detector detects that the movement of the tonneau cover to the storage position has been obstructed.
