A miniaturized power distributing device with harmonic suppression function and low cost is set in a substrate, and includes first, second, and third metal levels. The first metal level includes a power divider to divide one signal into multiple output signals, or to combine multiple input signals into one output signal. The second metal level includes a filter structure to filter out harmonics. The third metal level is isolated against electromagnetic wave signal leaking from the second metal level. The second metal level is set between the first and third metal levels, dielectric layers are set between the first and second metal levels and between the second and third metal levels.