A wearable device that may transform between an annularly bent state and a flat state is provided. The wearable device includes a plurality of segment members including a top portion and a bottom portion having a shorter length than the top portion; a plurality of connecting members that are disposed to correspond to the plurality of segment members, wherein each of the plurality of connecting members is connected to be mutually rotatable with two segment members disposed respectively on both sides thereof; a bistable spring that is supported on a plurality of segment members to provide elasticity in a direction into the annularly bent state and retentivity of the flat state; and a flexible display device that is supported on the top portion of the plurality of segment members.