Provided are a suspension bush and a suspension device that are able to achieve both steering operability and stability of a vehicle at the time of turning. A projection portion is formed on the outer circumference of an inner cylinder. A guide is formed on the inner circumference of an outer cylinder. In the guide, a slit is formed along an extending direction that includes: a component, in a parallel direction, which runs parallel with an axial line; and a component in a circumferential direction around the axial line. The projection portion is disposed in the slit, and a threaded mechanism is formed by the projection portion and the slit.