A walking assistance device includes a seating member configured to provide seating for a user; and leg links connected to the seating member. The seating member includes: a seating frame having at least two frames movably connected to each other; a bag member secured to the seating frame; filler contained in the bag member and freely movable in the bag member; and a valve provided on the bag member and capable of switching between a first state in which an inside of the bag member is in communication with an outside of the bag member and a second state in which the communication between the inside and the outside of the bag member is interrupted.