To solve the problems that a conventional secret postcard manufacturing device cannot print a recording medium other than a secret postcard and also print is transferred unless a printing surface is folded after sufficiently drying it.

The removable secret postcard manufacturing device, is mounted on a stacker part. First, the inner surface to be folded of the secret postcard, is printed, and a roller for folding the secret postcard is made of a water-repellent material.