This paper describes a basic heat transfer characteristic of pulsating flow in narrow cooling channel which can be observed in high-density packaging electronic equipment or miniature water cooling channel. There is a strong demand of miniaturization of cooling devices in order to decrease the dimensions of electronic equipment. However, due to the high pressure resistance in the miniature cooling devices, the supply flow rate of the working fluids is generally inhibited and the net cooling performance may become small unless a special miniature pump which has extremely high pressure characteristic is used. Therefore, an innovative idea of cooling technique for miniature electronic equipment should be investigated. Our research focuses on a pulsating flow likes a blood flow in our body. Through our previous studies, we reported that the cooling performance of the heating elements was enhanced by controlling the supply airflow rate periodically. By generating the pulsating airflow, the time-averaged supply flow rate of the cooling air becomes smaller than that of the steady airflow. However, the pulsating airflow can achieve almost the same cooling performance as the steady airflow. Through these backgrounds, in this report, we tried to apply the pulsating flow to the miniature ducts like flow passages in water coolers. We investigated a possibility of heat transfer enhancement in the miniature cooling channel by using the flow pulsation while decreasing the time-averaged supply flow rate of the working fluid in order to inhibit the power consumption of the fluid machineries. The investigation was proposed by the 3D-CFD (computational fluid dynamics) analysis. Through the research, we obtained basic information about the pulsating flow in the miniature flow passage.