Three-layer bonded structure containing artificial air defects within adhesive layers is manufufactured with the usage of building materials, insulation mat, and adhesive, and the specimen is inspected by the SynViewScan 300 continuous terahertz imaging system. Via analysing the two-dimensional terahertz images at adhesive surface and single point longitudinal signal within defect area and normal adhesive area, the informations about position and size of air defects are acquired.The results indicate that the continuous terahertz imaging system is capable of clear identification of air defects within bonded structures.