A separation apparatus for separating first pieces made of a first material and second pieces made of a second material, from a group of pieces that are separation subjects including the first pieces and the second pieces, the separation apparatus comprising: a conveyor that conveys, in one direction, the group of pieces placed on the conveyor; a material distinguishing unit to distinguish between the first pieces and the second pieces that are placed on the conveyor, according to material; a blower that generates airflow supplied from a middle of the conveyor toward a conveying end along a conveying surface on which the group of pieces is conveyed; a first separation unit to discharge airflow from a first group of nozzles to blow off the first pieces, from the group of pieces carried by the airflow from the blower from the conveying end that is an end of the conveyor and travelling a predetermined trajectory, based on a differentiation result obtained by the material distinguishing unit; a second separation unit, provided downstream from the first separation unit along the trajectory of the group of pieces, to discharge airflow from a second group of nozzles to blow off the second pieces toward a place different from a place toward which the first separation unit blows off the first pieces, based on the differentiation result, the second pieces being blown off from the group of pieces carried by the airflow from the blower from the conveying end that is the end of the conveyor and travelling the predetermined trajectory; characterized by a current plate, configured to adjust the airflow to flow along the trajectory, provided below and along the trajectory of the group of pieces and protruding from the conveyor, along the conveying surface, in a direction in which the group of pieces are thrown forward, the current plate having a starting end besides the conveying surface and an upper surface below the trajectory of the group of pieces. a conveyor that conveys, in one direction, the group of pieces placed on the conveyor; a material distinguishing unit to distinguish between the first pieces and the second pieces that are placed on the conveyor, according to material; a blower that generates airflow supplied from a middle of the conveyor toward a conveying end along a conveying surface on which the group of pieces is conveyed; a first separation unit to discharge airflow from a first group of nozzles to blow off the first pieces, from the group of pieces carried by the airflow from the blower from the conveying end that is an end of the conveyor and travelling a predetermined trajectory, based on a differentiation result obtained by the material distinguishing unit; a second separation unit, provided downstream from the first separation unit along the trajectory of the group of pieces, to discharge airflow from a second group of nozzles to blow off the second pieces toward a place different from a place toward which the first separation unit blows off the first pieces, based on the differentiation result, the second pieces being blown off from the group of pieces carried by the airflow from the blower from the conveying end that is the end of the conveyor and travelling the predetermined trajectory; characterized by a current plate, configured to adjust the airflow to flow along the trajectory, provided below and along the trajectory of the group of pieces and protruding from the conveyor, along the conveying surface, in a direction in which the group of pieces are thrown forward, the current plate having a starting end besides the conveying surface and an upper surface below the trajectory of the group of pieces.