Provided is a 1,3,4-oxadiazole-2-carboxamide compound which has STAT3 inhibitory activity and is useful as an anticancer agent. Provided is a 1,3,4-oxadiazole-2-carboxamide compound represented by formula (I) or a pharmacologically acceptable salt thereof (in the formula, Ar represents a furyl group or the like R1 represents a hydrogen atom or the like and —X—Y represents a diaryl group such as a biphenyl group).
