A liquid ejecting apparatus includes an ejecting unit capable of ejecting a liquid, a support unit configured to support a medium onto which the liquid is ejected and is movable in a movement direction between a set position where the medium is set and an ejecting start position where the ejecting unit starts ejecting the liquid, and a detector configured to detect whether an interference substance which is a substance that causes an interference with the ejecting unit is present on the support unit. The detector is movable between a first position and a second position, a distance between the second position and the ejecting unit being longer than a distance between the first position and the ejecting unit, in the movement direction.