The present invention provides fused heterocyclic derivatives represented by the general formula: wherein R1 represents H, halogen, OH, etc.; R2 represents H, halogen or an alkyl group; R3 and R4 represent H, OH, halogen, etc.; Q represents alkylene, etc.; ring A represents aryl or heteroaryl; and G represents , or pharmaceutically acceptable salts thereof, or prodrugs thereof, which exhibit an excellent inhibitory activity in human SGLT and are useful as agents for the prevention or treatment of a disease associated with hyperglycemia such as diabetes, postprandial hyperglycemia, impaired glucose tolerance, diabetic complications or obesity, pharmaceutical compositions comprising the same, and pharmaceutical uses thereof.