A seat includes a seat main body (12); first and second adjustable portions (14, 16, 18), each of which is provided on the seat main body and is placed in an adjustable state by operating force; an operating member (40) which is displaced in a predetermined range; a first operating force transmitting portion (66A) for transmitting the operating force of the operating member to the first adjustable portion (14) when the operating member is displaced in a first range; a second operating force transmitting portion (68) for transmitting the operating force of the operating member to the second adjustable portion (16, 18) when the operating member is displaced in a second range; and an operation reaction force avoiding portion for keeping the first adjustable portion in the state that it is in when the operating member is displaced in the first range, when the operating member is displaced in the second range, by the input operating force.