In the present invention, 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 is characterized by having: 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. The wavelength selection switch is further characterized in that when configuring n wavelength selection switches on the same substrate, at least one of the constituent elements is shared among the n.
