We present the results of radio observations of red supergiants in a star cluster, Stephenson (1990AJ.....99.1867S)'s #2 (Cl Stephenson 2), and of candidates for red supergiants in three star clusters, Mercer et al. (2005ApJ...635..560M)'s #4, #8, and #13 ([MCM2005b] 4, [MCM2005b] 8 and [MCM2005b] 13), in the SiO and H_2_O maser lines. The Stephenson's #2 cluster and nearby aggregation at the southwest contain more than 15 red supergiants.