Abstract: A wheelchair has a width that can be adjusted. The wheelchair has a pair of side frames connected to each other by one or more X-frame(s) (11). The X-frame (11) has a pair of rotatable arms connected rotatably to each other at their respective centers, the lower ends of each rotatable arm being fixed to the side frame, and the fixing position of each rotatable arm to the side frame is vertically adjustable. In the wheelchair (1), when the rotatable arm(s)(11A,HA) of the X-frames(s)(11) rotate around the centers C of the rotatable arms (s)(11A,11A), the width between the side frames (3,3) can be adjusted. When the rotatable arm(s) (11A,11A) are respectively rotated, the height of the X-frame(s) (11) is changed. However, since the lower part(s) of the X-frame(s) (11) is(are) fixed to the left and right side frames (3,3), and are vertically adjustable, the left and right side frames (3,3) can be connected by the X-frames(s) (11) to correspond to the change of the height of the X-frame(s) (11).