To analysis the effect by the Harmonics through Power facilities in Apartment housing, This paper measured the Harmonics at Lighting Transformer, Power Transformer and Services-entrance Conductors of electrical installation in apartment housing. The measured result is following as : 1) The Harmonics at Lighting Transformer is generated in the large of the 5th Harmonics. 2) The Harmonics at Power Transformer is generated in the large of the 5th and 7th Harmonics. And then 3) The THD at the Services-entrance Conductors is average 2.4[%], which is compared to the measuring Voltage, this meaning value is good condition until now against Harmonics effect. But, So the large capacitance of household electrical alliances with rectifiers in the future considered the effect of Harmonics at the Electric Power planning in apartment Housing.