Thirty two thiourea derivatives were prepared and their agonistic activities on the retinoic acid receptor-related orphan receptor ${alpha}$ ($ROR{alpha}$) were evaluated. The replacement of the 3-allyl-2-imino-thiazolidin-4-one moiety of the lead compound CGP52608 (1) with various functional group substituted aromatic rings, improved the agonistic activity of $ROR{alpha}$. Among the prepared derivatives, 1-methyl-3-(4-phenoxy-benzyl)-thiourea (32) showed 2.6-fold higher agonistic activity than CGP52608 in the $ROR{alpha}$-activation assay.