Abstract: A detection device detects a position of a leading end of a tip for executing an operation on a cell via the leading end, the tip including the leading end in a lower portion thereof. The detection device includes a light source that outputs light in a lateral direction such that the light has a width when viewed along an up-and-down direction, a movement mechanism that moves the tip, and a detector that detects the light output from the light source, wherein the light output from the light source until being detected by the detector includes first light and second light that advance in respective lateral directions that are different from each other, the movement mechanism moves the tip such that a part of the first light and a part of the second light are blocked by the leading end, and the detector detects the first light and the second light whose parts are blocked by the leading end.