To enhance network band utilization efficiency and throughput of a high order layer in a transmitter.

The transmitter for transmitting an input traffic from a plurality of ports on a synchronous optical communication network/synchronous digital hierarchy path set with an arbitrary bandwidth by virtual linking and a link capacity regulation system comprises a section for collecting input traffic for one period of each input port at a preset period and holding the collected input traffic, a band setting section for calculating the use band of each input port from the input traffic held in the input traffic collecting section, calculating the number of virtual linking member paths based on the difference from a virtual linking path band already assigned to the input port and issuing add/delete commands of the calculated number of virtual linking member paths, and a link capacity regulation system control section for controlling virtual linking by the add/delete commands of the virtual linking member path issued from the band setting section.