To provide a film unit wrapping body with lens and a mailing developing system which enable mailing and sending a reply of a developed negative film and a print to user.

This film unit wrapping body with lens is formed by housing a film unit 2 with lens and an envelope 3 for mailing which is used when the used film unit 2 with lens is mailed to a developing station into a wrapping bag 5, therein, on the surface of the envelope 3 for mailing, the address destination of a developing station to be mailed is printed and, on the back surface thereof, a seal 3c in which a column for the address destination of a sender is printed is strippably stuck. In addition, after finishing the use of the film unit 2 with lens, the film unit 2 with lens is enveloped into the envelope 3 for mailing on whose column the address to be sent back is entered and is mailed to the developing station. At the developing station, the photographed film is taken out of the film unit 2 with lens which is sent by mailing and is subjected to developing and printing processing and, thereafter, the negative film 8 and the printed photograph 9 are enveloped into an envelope 6 for sending back and, at the same time, the seal 3c stripped off from the back surface of the envelope 3 for mailing is stuck on the surface of the envelope 6 for sending back and is sent back.