A separation device separates a recording medium ejected from a fixing nip formed between a first rotator and a second rotator from the first rotator. The separation device includes a separator including a front end disposed opposite the fixing nip and the recording medium and a plurality of recesses disposed on the front end of the separator at least in a conveyance span on the separator where the recording medium is conveyed. The plurality of recesses includes a first recess extending in a first extension line that is oblique relative to a recording medium conveyance direction and a second recess adjacent to the first recess and extending in a second extension line that is oblique relative to the recording medium conveyance direction. The second extension line overlaps the first extension line in a direction perpendicular to the recording medium conveyance direction to define an overlap span.