To provide a seal that can be affixed in an exact position and straight on a document when sealed.

A transparent seal holder 1a is provided with a seal part 1b to form a transparent seal 1 and supported by springs so that a marking surface 1c of the seal part 1b has a clearance between itself and the document 4 in a state of placing the transparent seal 1 on the document. The seal holder 1a is configured such that the marking surface 1c comes into contact with the document when pressed down and is restored into the original state after the end of pressing. A sealed part can be confirmed by seeing through the transparent seal holder 1a. There is also an effect of sealing the document straight by pressing the seal holder 1a with a finger.