Global dimension of Harada rings and serial rings

Baba [On Harada rings and quasi-Harada rings with left global dimension at most 2. Comm. Algebra 28(6) (2000) 2671-2684] proved that every left Harada rings with global dimension at most 2 is a serial ring. In this paper, improving the result, we show that every left Harada ring with global dimension at most 3 is a serial ring. We also prove that if a left Harada ring A of finite global dimension is of type (*) or has homogeneous right socle, then A is serial. Finally, we give an example of a non-serial left Harada ring of finite global dimension.