The invention provides a multicast switch array and a multi-beam steering device using the multicast switch array. The beam steering apparatus includes: a switch array including a plurality of switches connected to a first waveguide into which light is input; and a plurality of grating couplers connected with the plurality of switches, where the plurality of switches are arranged in a row on the plane of the substrate along the first waveguide, and each of the plurality of switches provides a second waveguide for passing light to one of the plurality of grating couplers according to on/off of each switch. Therefore, large-scale multi-beam direction adjustment can be accurately carried out.
