A boring device according to the present invention includes: a hollow main shaft; a table supporting the main shaft rotatably about a predetermined axis; a tool holder extending in the form of a bar and configured to rotate coaxially with the main shaft; a radially protruding tool provided at a distal end portion of the tool holder; a tilting unit provided between the main shaft and the tool holder in the axis direction and configured to cause the tool holder to be inclined from the axis; a drawbar configured to be movable back and forth in the axis direction within the main shaft; a first drive unit configured to rotate the main shaft about the axis; and a second drive unit configured to move the drawbar back and forth in the axis direction.