To provide an envelope or the like onto which a message or the like can be easily hand-written or printed just before an insert such as a letter or money is inserted and which can be opened to develop the message written on the inside of the envelope on a sheet of paper to read the message like a letter.

The envelope or the like has a sealing strip provided continuously without a break with the outer rim of the insert opening of an upper side paper, the upper side paper constituting the envelope with a lower side paper having a cutout smaller in form or size than the sealing strip by the size of the tab for sticking, and the envelope or the like is so arranged that the writing and printing, etc., of a message, etc., can be provided on the sealing strip in the inside of its tab for sticking, and on the portion of the inside of the upper side paper that is exposed through the cutout which is provided on the lower side paper, smaller in form or size than the sealing strip by the size of the strip's tab for sticking, the portion being provided continuously without a break with the sealing strip. The periphery rim of at least either the upper or lower side paper is formed like a belt to be an adhesive layer or configured by perforations, etc., in a peelable or removable state, thus the envelope can be developed into a state of a piece of paper, by peeling or removing the upper side paper and the lower side paper sealed with the sealing strip, from the peel or removal starting portion provided in advance at the periphery portion of the paper opposite to the throw-in opening.