The interfacial strength and the interfacial fracture toughness between a carbon fiber and epoxy resin are evaluated by using the microbond test. Four types of specimens which consist of an epoxy resin with different hardeners and fibers with different surface treatments (with and without sizing treatment) are used. Tests are performed at room temperature, 50℃, 80℃ and -10℃. It is found that the interfacial shear strength is lower for the fibers without sizing treatment and the tendency is enhanced at higher temperatures. The validity of the microbond test is also discussed through the SEM observation of the fracture appearance of specimens. A model microbond test is performed to observe failure process. FEM analysis is conducted to discuss the experimental results.