To provide a three-dimensional display medium which enhances the effect to propagate information by enticing the interest of a card recipient and can be applied to a non-bulky sealed letter or the like.

The display medium applicable to the sealed letter 21 is structured as described below. A sheet for making out a sealed letter 21 consisting of a first paper piece 5, a second paper piece 6, a third paper piece 7 and a fourth paper piece 8 connected together through three perforations 3 and 4 for folding, is replicated in a zigzag fashion by the perforations 3 and 4 so as to show an address display surface of the first paper piece 5. In addition, each replicated surfaces of the first paper piece 5/the second paper piece 6 and the third paper piece 7/the fourth paper piece 8, are bonded together in the way that the mating parts of a three-dimensional display parts 10a and 10b are difficult to peel from each other and the other parts can be peeled or difficult to peel from each other. On the other hand, the mutually superposed surfaces of the second paper piece 6 and the third paper piece 7 are bonded together in the way that the surfaces can be spread and each three-dimensional display part 10a and 10b three-dimensionally stands up to show a piece of three-dimensional display information 15b and pieces of revealed information 16a and 16b, when the paper pieces 6 and 7 are spread.