The present invention provides a marker unit that can be easily installed in the same target object under the same installation condition, for example. The marker unit of the present invention includes: an upper substrate; and a lower substrate, wherein the upper substrate is laminated on the lower substrate to form a laminate. The lower substrate has a lower substrate detection target portion exposed to an upper surface side of the laminate on an upper surface thereof, and the lower substrate has at least two positioning portions on a lower surface thereof. The detection target portion is detectable from an upper surface side of the laminate, and each positioning portion is visually recognizable from a side surface direction of the laminate and is visually unrecognizable from the upper surface direction of the laminate. When the laminate is installed in an installation target object, each positioning portion is disposed on the lower substrate at a position corresponding to an alignment mark with the marker unit in the installation target object by recognizing from the side surface direction of the laminate.