Disclosed are a support device for a string instrument and a string instrument having the same, the support device being easily stored without an unnecessary separate attachment/detachment process. The support device for a string instrument includes: fixing plates fixed to a body of a string instrument; a first rotary plate rotatably connected to the fixing plates; and a second rotary plate rotatably coupled to the first rotary plate, wherein the first rotary plate has a shape corresponding to one part of a side plate of the body, and the second rotary plate has a shape corresponding to another part of the side plate of the body which is different from one part of the side plate of the body.