There is provided an interposer for cooling an electronic component. The interposer includes: a substrate body having a hollow cooling channel therein, wherein a cooling medium flows through the cooling channel, the cooling channel including: a plurality of main cooling channels extending in a certain direction and separated from each other; an inflow channel which is communicated with one end of the respective main cooling channels; and an outflow channel which is communicated with the other end of the respective main cooling channels, and a plurality of through electrode groups each comprising a plurality of through electrodes arranged in a line. Each of the though electrodes is formed through the substrate body to reach the first and second surfaces of the substrate body. The respective through electrode groups are partitioned by at least corresponding one of the main cooling channels.