To solve the following problems: in general, scissors are used for opening an envelope, however a user is frustrated by moving his or her hand; or when the user uses a dedicated opener, he or she has to set a cutting edge of the opener at a few-mm opening of an envelope carefully, which is inconvenient.

An envelope opener is formed in the shape of a clip and is provided with a shaft of a stopper to be brought into contact with an end of an envelope, thereby allowing the sealed opening part to be easily held. The envelope can be opened only by simply sliding the opener which is easy to use and convenient.