Electron cyclotron emission (ECE) imaging has been an important tool to investigate behaviors of temperature perturbations in the specific spatial area. So far, we have applied ECE detection system to a LHD plasma to measure electron temperature fluctuations in core region, however, it was difficult to distinguish perturbed temperature signals to a noise, which is naturally consisted in radiometry features and so on. Recently, we have optimized an ECE detector array especially in sensitivity to increase signal to noise ratio. An intermediate frequency(IF) system composed of commercial components have been replaced by an integrated system utilizing millimeter(microwave) integrated circuit technology(MIC) to fabricate a compact system maintaining the performance of the commercial system. As a result of application to the LHD plasma, we have successfully obtained ECE signal even in comparably low temperature operation sequence.