Abstract: A 5-membered heteroaromatic ring compound represented by the formula [I] wherein V is CH or N; W is S or O; R1 and R2 are each H etc.; X is —N(R4)—, —O—, —S—, —SO2—N(R5)—, —CO—N(R7)— etc.; L is wherein R20, R21, R22 and R25 are each H etc.; E is aryl or heteroaromatic ring group; R is —COOH etc.; B is aryl etc.; R3 is H etc.; Y is —C(R13)(R14)—N(R12)—C(R13)(R14)—O—, —N(R11)—, —O— etc.; A is alkylene; and Z is aryl etc., a prodrug thereof and a pharmaceutically acceptable salt thereof. The compound [I] has a superior protein tyrosine phosphatase 1B inhibitory activity and is useful as a therapeutic agent for diabetes, diabetic complications, hyperlipidemia, obesity and the like.