Recently, there has been an increasing demand for low-power LED lighting fixtures that can contribute to a low-carbon society, however because AC voltage cannot be used directly for LEDs, an ACDC power converter is required for the LED equipment. Therefore, a buck converter as an ACDC power converter is applied to the LED equipment, but the effect of electromagnetic interference (EMI) becomes an issue which cannot be ignored in wireless communication equipment. In particular, because EMI radiated emission becomes a significant problem of communication signal discontinuations, the input of the buck converter has to be installed the EMI reduction filter equipment. This research shows EMI disturbance characteristics when a buck type current control DCDC converter circuit is used for an LED lighting equipment, and reports experimental results of EMI radiated emission characteristics improvement by changing the input and output circuit constants. Moreover, it is shown that can reduce to the floor noise level (background noise) when an output chip capacitor is inserted without an input filter.