Overclocking due to the disruption of a clock signal sometimes causes malfunctions (i.e., temporal faults) in LSI modules. It is known that electromagnetic interference can also cause overclocking. However, there is no specific method for detecting the occurrence of such overclocking in LSI modules. This paper proposes a method for detecting overclocking in LSI modules and its implementation as a detection circuit. We evaluate the validity of the proposed circuit through two kind of experiments (i) with a clock signal with artificially-inserted glitches and (ii) with CWs injected externally. From the 1st experiment, we confirm that our detection circuit can correctly determine whether overclocking (i.e., glitchy clock signal) is generated or not. From the 2nd experiment, we observe that the output sequence of our detection circuit indicates the occurrence of overclocking by injected CWs. At the same time, we also show the corresponding fluctuation in the voltage of clock signal due to the overlapped CW.