A drum unit includes a photosensitive drum and a cleaning member. A scratch remaining depth measured by a scratch test of the photosensitive drum under a following Test Condition 1 is 110 nm or less. Test Condition 1 is; test environment temperature=25° C.; test environment humidity=50%; test indenter=pre-mount type Berkovich indenter; scratch direction=horizontal direction; scratch speed=20 μm/sec; initial load=0 mN; maximum reaching load=4 mN; and load at the time of measuring the scratch remaining depth=1.9 mN.