To provide a mulching-film remaining amount detection device which prevents a mulching film from not being laid down on ridges while mulching work is performed by a mulcher.SOLUTION: The mulching-film remaining amount detection device comprises: a rotation body 92 which comes into contact with a surface of a film roll R wound with a mulching film M to be laid down on a farm field, and which rotates as the film roll R rotates; a detection sensor 95 which detects rotation of the rotation body 92; and a notification device which makes notification as to the remaining amount of the mulching film M wound on the film roll R, on the basis of a detection result of the detection sensor 95.SELECTED DRAWING: Figure 2【課題】マルチ作業機による作業時に、畝にマルチフィルムが敷設されないことを防止したマルチフィルム残量検出装置を提供する。【解決手段】圃場に敷設されるマルチフィルムMが巻回されたフィルムロールRの表面に当接し且つフィルムロールRの回転に伴って回転する回転体92と、回転体92の回転を検出する検出センサ95と、検出センサ95による検出結果に基づいてフィルムロールRに巻回されたマルチフィルムMの残量状態を報知する報知装置と、を備えているマルチフィルム残量検出装置。【選択図】図2