A conveyance seat comprising: a seat base on which an occupant sits; a support portion which supports the occupant from a back side; a flip-up mechanism which flips up the seat base; a biasing member which biases the support portion forward so that the support portion is inclined forward; the support portion is engageable with an engagement portion of a vehicle body to hold the support portion in an upright state against a biasing force of the biasing member; a cancel mechanism which cancels an engagement between the engagement portion and the support portion by using a flip-up operation using the flip-up mechanism; and a return mechanism which performs a return operation of returning the support portion from a state where the engagement with the engagement portion is canceled by the cancel mechanism to a state where the support portion is engageable with the engagement portion, characterized in that the return mechanism performs the return operation in accordance with an inclination angle of the support portion inclined forward by a biasing force of the biasing member after the engagement between the engagement portion and the support portion is canceled, wherein the engagement between the engagement portion and the support portion is canceled after the flip-up operation starts, and wherein the return mechanism performs the return operation at a time when the inclination angle of the support portion reaches a predetermined set angle after the support portion starts to be inclined forward by the biasing force of the biasing member by canceling the engagement between the engagement portion and the support portion. a seat base on which an occupant sits; a support portion which supports the occupant from a back side; a flip-up mechanism which flips up the seat base; a biasing member which biases the support portion forward so that the support portion is inclined forward; the support portion is engageable with an engagement portion of a vehicle body to hold the support portion in an upright state against a biasing force of the biasing member; a cancel mechanism which cancels an engagement between the engagement portion and the support portion by using a flip-up operation using the flip-up mechanism; and a return mechanism which performs a return operation of returning the support portion from a state where the engagement with the engagement portion is canceled by the cancel mechanism to a state where the support portion is engageable with the engagement portion, characterized in that the return mechanism performs the return operation in accordance with an inclination angle of the support portion inclined forward by a biasing force of the biasing member after the engagement between the engagement portion and the support portion is canceled, wherein the engagement between the engagement portion and the support portion is canceled after the flip-up operation starts, and wherein the return mechanism performs the return operation at a time when the inclination angle of the support portion reaches a predetermined set angle after the support portion starts to be inclined forward by the biasing force of the biasing member by canceling the engagement between the engagement portion and the support portion.