A blade position registering apparatus for registering the positions of blades of turning process tools (40, 45) capable to be provided in a combined lathe apparatus having a tool holder and tool spindle having an axis (X-axis) which is inclined with respect to a horizontal line (Yt) by a predetermined angle θ which is greater than zero degree and less than or equal to 90 degrees, the blade position registering apparatus being characterized in that a reference point is provided on the axis (X-axis) of the tool spindle, the blade position registering apparatus comprising: blade position inputting means for inputting a first tool length (Ca) which is an amount of offset by which the blade of a horizontal turning process tool (40, 45) is offset from the reference point along the Z axis being the axis of the workpiece, a second tool length (Cb) which is an amount of offset by which the blade of the horizontal turning process tool (40, 45) is offset from the reference point along a horizontal line (Yt) which is perpendicular to the Z axis, a third tool length (Cc) which is an amount of offset by which the blade of the horizontal turning process tool (40, 45) is offset from the reference point along a vertical line, a fourth tool length which is an amount of offset by which the blade of a tool for turning in a X-axis-Z-axis plane is offset from the reference point along an axis being the Z-axis which is perpendicular to the tool spindle axis being the X-axis, and a fifth tool length (a) which is an amount of offset by which the blade of the tool for turning in a X-axis-Z-axis plane is offset from the reference point along the X-axis; and storage means for storing the inputted first tool length (Ca), the second tool length (Cb), the third tool length (Cc), the fourth tool length and the fifth tool length (a). blade position inputting means for inputting a first tool length (Ca) which is an amount of offset by which the blade of a horizontal turning process tool (40, 45) is offset from the reference point along the Z axis being the axis of the workpiece, a second tool length (Cb) which is an amount of offset by which the blade of the horizontal turning process tool (40, 45) is offset from the reference point along a horizontal line (Yt) which is perpendicular to the Z axis, a third tool length (Cc) which is an amount of offset by which the blade of the horizontal turning process tool (40, 45) is offset from the reference point along a vertical line, a fourth tool length which is an amount of offset by which the blade of a tool for turning in a X-axis-Z-axis plane is offset from the reference point along an axis being the Z-axis which is perpendicular to the tool spindle axis being the X-axis, and a fifth tool length (a) which is an amount of offset by which the blade of the tool for turning in a X-axis-Z-axis plane is offset from the reference point along the X-axis; and a first tool length (Ca) which is an amount of offset by which the blade of a horizontal turning process tool (40, 45) is offset from the reference point along the Z axis being the axis of the workpiece, a second tool length (Cb) which is an amount of offset by which the blade of the horizontal turning process tool (40, 45) is offset from the reference point along a horizontal line (Yt) which is perpendicular to the Z axis, a third tool length (Cc) which is an amount of offset by which the blade of the horizontal turning process tool (40, 45) is offset from the reference point along a vertical line, a fourth tool length which is an amount of offset by which the blade of a tool for turning in a X-axis-Z-axis plane is offset from the reference point along an axis being the Z-axis which is perpendicular to the tool spindle axis being the X-axis, and a fifth tool length (a) which is an amount of offset by which the blade of the tool for turning in a X-axis-Z-axis plane is offset from the reference point along the X-axis; and storage means for storing the inputted first tool length (Ca), the second tool length (Cb), the third tool length (Cc), the fourth tool length and the fifth tool length (a).