To provide a vertically movable chair appropriate for a physically handicapped person to stand up when he/she is on a tatami or inversely to sit down on the tatami.

In a chair of the structure with a vertically movable seat, the seat of the chair ascends by mounting an extendible fluid container 8 vertically under the seat and forcing fluid into the container 8 using a compressor 9, and the seat descends by drawing fluid out of the container 8. Turning a switch 17 on/off enables the seat to ascend/descend electrically.