A turning control device using a turning device including: a spindle to be rotated with a workpiece held thereon; a tool holding unit for holding a tool for turning the workpiece; a Z-axis driving unit for displacing at least one of the spindle and the tool holding unit in a Z-axis direction which is a direction parallel to a rotation axis of the spindle; an X-axis driving unit for displacing at least one of the spindle and the tool holding unit in an X-axis direction orthogonal to the Z axis; and a B-axis driving unit for inclining the tool holding unit around a Y axis orthogonal to both of the Z axis and the X axis, to rotate the workpiece held on the spindle and relatively feed the tool in at least the Z-axis direction in a cutting state in a predetermined cutting depth (ap) in the X-axis direction with respect to the workpiece, thereby performing turning work, the turning control device comprising: a storage unit for storing a working program for defining the turning work and tool shape data indicative of a shape of the tool; a working program processing unit for analyzing the working program and calculating and outputting command amounts for the Z-axis driving unit, the X-axis driving unit, and the B-axis driving unit; a command value setting processing unit for setting an approach angle command value for defining an approach angle (α) which is an angle formed by a cutting edge of the tool and a direction orthogonal to a relative feeding direction of the tool with respect to the workpiece when performing the turning work; an approach angle setting command amount calculation processing unit for calculating, as an approach angle setting command amount, a B-axis command amount for controlling to cause the approach angle (α) to have the approach angle command value based on the tool shape data; and a command processing unit for outputting the approach angle setting command amount to the B-axis driving unit, wherein the working program includes cutting depth data for defining a cutting depth and approach angle data for defining the approach angle (α), the turning control device further comprises an approach angle calculation processing unit configured to calculate the approach angle (α) at which an absolute value of a thrust force to be applied to the workpiece by the tool is equal to or smaller than a specified value by using thrust force data including information about cutting speed or feeding speed when performing the turning work according to the cutting depth data of the working program, the approach angle calculation processing unit is configured to register the calculated approach angle as the approach angle data into the working program, and the command value setting processing unit is configured to set the approach angle data to the approach angle command value. a spindle to be rotated with a workpiece held thereon; a tool holding unit for holding a tool for turning the workpiece; a Z-axis driving unit for displacing at least one of the spindle and the tool holding unit in a Z-axis direction which is a direction parallel to a rotation axis of the spindle; an X-axis driving unit for displacing at least one of the spindle and the tool holding unit in an X-axis direction orthogonal to the Z axis; and a B-axis driving unit for inclining the tool holding unit around a Y axis orthogonal to both of the Z axis and the X axis, a storage unit for storing a working program for defining the turning work and tool shape data indicative of a shape of the tool; a working program processing unit for analyzing the working program and calculating and outputting command amounts for the Z-axis driving unit, the X-axis driving unit, and the B-axis driving unit; a command value setting processing unit for setting an approach angle command value for defining an approach angle (α) which is an angle formed by a cutting edge of the tool and a direction orthogonal to a relative feeding direction of the tool with respect to the workpiece when performing the turning work; an approach angle setting command amount calculation processing unit for calculating, as an approach angle setting command amount, a B-axis command amount for controlling to cause the approach angle (α) to have the approach angle command value based on the tool shape data; and a command processing unit for outputting the approach angle setting command amount to the B-axis driving unit, wherein the working program includes cutting depth data for defining a cutting depth and approach angle data for defining the approach angle (α), the turning control device further comprises an approach angle calculation processing unit configured to calculate the approach angle (α) at which an absolute value of a thrust force to be applied to the workpiece by the tool is equal to or smaller than a specified value by using thrust force data including information about cutting speed or feeding speed when performing the turning work according to the cutting depth data of the working program, the approach angle calculation processing unit is configured to register the calculated approach angle as the approach angle data into the working program, and the command value setting processing unit is configured to set the approach angle data to the approach angle command value.