A device having fool-proofing structure is configured to be inserted into a cabinet along a first direction and includes a case and an elastic sheet module. The elastic sheet module is disposed on a side of the case and includes a first end disposed on the case, a second end opposite to the first end, a first protrusion portion and a second protrusion portion. The first protrusion portion is adjacent to the second end, protrudes from the case and is configured to abut against the cabinet. The second protrusion portion is farther from the second end than the first protrusion portion, protrudes from the case, and is configured to make the second end and the first protrusion portion move toward the interior of the case as being pressed by a force.