Disclosed herein is a measurement apparatus for improving performances of standard cells in a standard cell library when verifying performance of the standard cell library through a ring oscillator among various test element groups (TEGs). A built-in circuit is used to measure and verify performance of the standard cell library through a TEG. Therefore, it is possible to effectively improve performances of the standard cells in the standard cell library. Particularly, it is possible to not only remove human errors or internal errors of equipment, but also perform the measurement more readily, rapidly and accurately. Further, it is possible to curtail the use of high-performance equipment or manpower and time required in a measurement process.