A multi-degree-of-freedom support mechanism includes a first member having a protruding part with a spherical surface, and a second member having a pair of planes opposite to each other across the protruding part. One of the first member and the second member is able to make relative movement with respect to the other with sliding movement of the spherical surface on the pair of planes. The pair of planes is in contact with the spherical surface. The relative movement includes translational movement in two degrees of freedom in planar direction and rotational movement about an axis in three degrees of freedom in the pair of planes.