PURPOSE: To perform efficiently the attaching and detacthing of a takeout seat, and to keep the appearance of the whole of the main seat beautiful, by incorporating detachably a takeout seat into part of the main seat, providing the botbom section of the takeout seat with a collapsible leg section, and arranging a cover member for covering the leg section.

CONSTITUTION: When a main seat 1 is used, a takeout seat 4 is contained in the main seat 1. For example when the takeout seat 1 is used outdoor, the takeout seat 4 is removed from the main seat 1. Then an anchoring member 12 such as a fastener located at the bottom section of a seat cushion 5 of the takeout seat 4 is opened to open a cover member 11, a pair of leg sections 7, 8 that have been covered with the cover member 11 are spread, and the cover member 11 is for example rolled not to be soiled. Thus, the takeout seat 4 can easily and quickly be contained into or taken out from the main seat 1, and since the leg sections 7, 8 are covered with the cover member 11, the main seat 1 would not be soiled when the takeout seat 4 is detached or attached.