To allow chairs for use in, e.g. a hospital to be easily converted into a bed or sofa during the night.

A chair is formed comprising a frame 2, a seat cushion and a back cushion which can be freely assembled to one another. For the seat part of the frame 2, an inner pipe 12 is slidable relative to an outer pipe 7a to allow adjustment of the depth of the seat part. The inner pipe 12 is pushed in to reduce the depth to allow the use of a chair. With the inner pipe 12 drawn out to increase the depth, two chairs are arranged in the direction of depth to provide a bed or sofa.