  The conformal symmetry on the instanton moduli space is discussed using the
ADHM construction, where a viewpoint of "homogeneous coordinates" for both the
spacetime and the moduli space turns out to be useful. It is shown that the
conformal algebra closes only up to global gauge transformations, which
generalizes the earlier discussion by Jackiw et al. An interesting
5-dimensional interpretation of the SU(2) single-instanton is also mentioned.
