A SCM-PON using WDM includes: an OLT for transferring downstream data from an external service provider through downstream optical signals and transferring upstream data transferred through upstream optical signals to an outside; an ODN for distributing the downstream optical signals from the OLT and multiplexing the upstream optical signals to the OLT; and a plurality of ONUs for processing the downstream optical signals transferred from the OLT through the ODN and transferring upstream data of subscribers for the OLT through the upstream optical signals, wherein the optical signals between the OLT and the ONUs are divided into wavelength channels with different wavelengths and sub-carrier channels obtained by time-dividing the wavelength channels, and the upstream data and the downstream data are transferred through the sub-carrier channels.