(Wherein n is an integer of from 0 to 3; R 1 is substituted or unsubstituted cycloalkyl, substituted or unsubstituted aryl, a substituted or unsubstituted alicyclic heterocyclic group, or a substituted or unsubstituted aromatic heterocyclic group; R 2 is halogen, substituted or unsubstituted lower alkyl, substituted or unsubstituted aryl, a substituted or unsubstituted alicyclic heterocyclic group, a substituted or unsubstituted aromatic heterocyclic group, -COR 8 , or the like; R 3 and R 4 may be the same or different, and each represents a hydrogen atom, substituted or unsubstituted lower alkyl, substituted or unsubstituted aralkyl, -COR 12 , or the like) For example, provided are adenosine A 2A receptor antagonists comprising, as the active ingredient, a thiazole derivative represented by a general formula (I), or a pharmaceutically acceptable salt thereof, and the like.