PURPOSE: To provide a bag by which a user can instantly sit down on a collapsible chair without searching a sitting place and which can preclude the possibility of losing the collapsible chair and troublesomeness of being housed in or taken out of a bag body and whose bag body and collapsible chair are integrally formed.

CONSTITUTION: Connecting members 4 to connect a collapsible chair 1 are arranged on the reverse of a bag body, and locking members 5 to lock the collapsible chair 1 at leg closing time in a freely mountable and demountable manner, are arranged at proper intervals from the connecting members 4, and the collapsible chair 1 is connected so that legs can be freely opened and closed.