Conveyance seat

A conveyance seat, comprising:

• a seat back frame;
• a skin material covering the seat back frame;
• a movable body arranged between the seat back frame and the skin material and protruding forward with respect to the seat back frame;
• and
• a control device controlling movement of the movable body, wherein
• the movable body has
• right and left first movable bodies arranged at upper parts of the seat back frame, and
• a second movable body arranged below the first movable bodies in the seat back frame,
• each of the first movable bodies is a shoulder movable body configured to support a shoulder of a seated occupant, the shoulder movable body including an inflatable and deflatable shoulder fluid bag,
• the second movable body is a lumbar movable body configured to support a waist of the seated occupant, the lumbar movable body including an inflatable and deflatable lumbar fluid bag, and
• the control device:
• acquires pressure signals related to pressure applied to the shoulder fluid bag and the lumbar fluid bag,
• determines a seating posture of the seated occupant by comparing determination conditions for determining the sitting posture of the seated occupant with the pressure signals, and
• based on a determination result of the seating posture, inflates one of the shoulder fluid bag and the lumbar fluid bag that corresponds to a part of the seated occupant that is bent forward in the seating posture, and
• deflates the other of the shoulder fluid bag and the lumbar fluid bag based on an amount of inflation of the one of the shoulder fluid bag and the lumbar fluid bag.