There is provided a contact structure, comprising a substrate contact including a first contact portion that is located on a leading end side of the substrate contact and that comes into contact with a substrate and a second contact portion that is located nearer to a base end side of the substrate contact than the first contact portion; a seal member configured to cover a periphery of the substrate contact and to have a sealing surface that comes into contact with the substrate to seal the substrate contact; a first pressing portion configured to elastically apply a contact pressure on the substrate to the substrate contact; and a second pressing portion configured to come into contact with the seal member and to apply a contact pressure on the substrate to the seal member independently of the first pressing portion, wherein the first contact portion adheres to the seal member, and the second contact portion is fit in the seal member to be displaceable relative to the seal member.