A wavelength selection switch can decrease the amount of increase in size and cost of a node device by integrating and sharing the constituent components of a plurality of wavelength selection switches or optical components mounted in a node. The wavelength selection switch has: at least one input port that inputs light; at least one output port that receives light from the input port; at least one light-collecting element that alters the beam shape of the light entering from the input port; at least one scattering element that scatters the light entering from the input port into each wavelength; at least one wavefront control element that causes light of each wavelength scattered by the scattering element to be reflected to the output port for each wavelength.