[Problem] To provide a compound which is useful as a GK activator. [Means for Resolution] As a result of an extensive study on thiazole derivatives, the present inventors have found that a compound having an oxamoyl group, a glycol group or the like on a thiazole ring and a compound having an acetamide group substituted by a bicyclic heteroaryl group such as a quinolyl have a good GK activation effect, and thereby have accomplished the present invention. Since the compounds of the present invention have a good GK activation effect, these are useful as therapeutic agents for diabetes, particularly type II diabetes.