A work positioner, comprising: a first work retaining portion for retaining a first workpiece; a first drive portion for outputting a first rotational force about a first rotation axis (RAX, RX1) and imparting a first angular movement about the first rotation axis (RAX, RX1) to the first work retaining portion; a bearing portion supporting the first work retaining portion in cooperation with the first drive portion; a base arranged away from the first rotation axis (RAX, RX1); a first support column extending along a first support axis extending from the base toward the first rotation axis (RAX, RX1), the first support column supporting the first drive portion; and a second support column extending along a second support axis extending between the base and the first rotation axis (RAX, RX1) so as to be parallel to the first support axis, the second support column supporting the bearing portion, characterised in that the first support column includes a plurality of first support column pieces arranged in a row along the first support axis so as to enable to increase or decrease a distance between the first rotation axis (RAX, RX1) and the base by respectively removing or adding one or more of said first support column pieces, the top one of the plurality of first support column pieces supporting the first drive portion, the second support column includes a plurality of second support column pieces arranged in a row along the second support axis so as to enable to increase or decrease a distance between the first rotation axis (RAX, RX1) and the base by respectively removing or adding one or more of said second support column pieces, the top one of the plurality of second support column pieces supporting the bearing portion, each of the plurality of second support column pieces is equal in shape and size to the plurality of first support column pieces, and the base includes a first base portion disposed at a position intersecting the first support axis, a second base portion disposed at a position intersecting the second support axis, and an intermediate base portion disposed between the first base portion and the second base portion, and further comprising: a first rail (171, 172) installed on the first base portion and extending parallel to the first rotation axis; and a second rail (173, 174) installed on the second base portion and extending parallel to the first rotation axis, wherein the first support column is positionally adjustable along the first rail (171, 172), and the second support column is positionally adjustable along the second rail (173, 174). a first work retaining portion for retaining a first workpiece; a first drive portion for outputting a first rotational force about a first rotation axis (RAX, RX1) and imparting a first angular movement about the first rotation axis (RAX, RX1) to the first work retaining portion; a bearing portion supporting the first work retaining portion in cooperation with the first drive portion; a base arranged away from the first rotation axis (RAX, RX1); a first support column extending along a first support axis extending from the base toward the first rotation axis (RAX, RX1), the first support column supporting the first drive portion; and a second support column extending along a second support axis extending between the base and the first rotation axis (RAX, RX1) so as to be parallel to the first support axis, the second support column supporting the bearing portion, characterised in that the first support column includes a plurality of first support column pieces arranged in a row along the first support axis so as to enable to increase or decrease a distance between the first rotation axis (RAX, RX1) and the base by respectively removing or adding one or more of said first support column pieces, the top one of the plurality of first support column pieces supporting the first drive portion, the second support column includes a plurality of second support column pieces arranged in a row along the second support axis so as to enable to increase or decrease a distance between the first rotation axis (RAX, RX1) and the base by respectively removing or adding one or more of said second support column pieces, the top one of the plurality of second support column pieces supporting the bearing portion, each of the plurality of second support column pieces is equal in shape and size to the plurality of first support column pieces, and the base includes a first base portion disposed at a position intersecting the first support axis, a second base portion disposed at a position intersecting the second support axis, and an intermediate base portion disposed between the first base portion and the second base portion, and further comprising: a first rail (171, 172) installed on the first base portion and extending parallel to the first rotation axis; and a second rail (173, 174) installed on the second base portion and extending parallel to the first rotation axis, wherein the first support column is positionally adjustable along the first rail (171, 172), and the second support column is positionally adjustable along the second rail (173, 174). a first rail (171, 172) installed on the first base portion and extending parallel to the first rotation axis; and a second rail (173, 174) installed on the second base portion and extending parallel to the first rotation axis, wherein the first support column is positionally adjustable along the first rail (171, 172), and the second support column is positionally adjustable along the second rail (173, 174).