A dental treating apparatus, comprising: a hand piece for drivably holding a cutting tool on a head unit; a driving unit (7, 13) for driving said cutting tool so as to be rotatable in a normal rotation direction in which said cutting tool is able to cut an object and in a reverse rotation direction opposite to said normal rotation direction; a control unit for controlling a rotation direction of said cutting tool; a load detecting unit for detecting a load applied to said cutting tool; and a load comparing unit for comparing the load detected by said load detecting unit and a reference load, wherein until a predetermined first condition is satisfied, said control unit maintains the rotation direction of said cutting tool in said normal rotation direction, even if the detected load is equal to or larger than the reference load; during driving in said normal rotation direction by said driving unit (7, 13) until said predetermined first condition is satisfied, said load comparing unit compares the load detected by said load detecting unit and said reference load; when the predetermined first condition is satisfied and the detected load is equal to or larger than the reference load, said control unit controls the rotation direction of said cutting tool to said reverse rotation direction; when a predetermined second condition is satisfied, said control unit controls the rotation direction of said cutting tool to be switched from said reverse rotation direction to said normal rotation direction; said predetermined first condition is set by a setting unit based on a rotation angle or a rotation time when said driving unit (7, 13) drives said cutting tool in said normal rotation direction, and the satisfaction of the predetermined first condition defines a timing for switching driving to said reverse rotation direction, and wherein said predetermined second condition is set by the setting unit based on a reverse rotation angle or a reverse rotation time when said driving unit (7, 13) drives said cutting tool in said reverse rotation direction, and the satisfaction of the predetermined second condition defines a timing for switching driving to said normal rotation direction. a hand piece for drivably holding a cutting tool on a head unit; a driving unit (7, 13) for driving said cutting tool so as to be rotatable in a normal rotation direction in which said cutting tool is able to cut an object and in a reverse rotation direction opposite to said normal rotation direction; a control unit for controlling a rotation direction of said cutting tool; a load detecting unit for detecting a load applied to said cutting tool; and a load comparing unit for comparing the load detected by said load detecting unit and a reference load, wherein until a predetermined first condition is satisfied, said control unit maintains the rotation direction of said cutting tool in said normal rotation direction, even if the detected load is equal to or larger than the reference load; during driving in said normal rotation direction by said driving unit (7, 13) until said predetermined first condition is satisfied, said load comparing unit compares the load detected by said load detecting unit and said reference load; when the predetermined first condition is satisfied and the detected load is equal to or larger than the reference load, said control unit controls the rotation direction of said cutting tool to said reverse rotation direction; when a predetermined second condition is satisfied, said control unit controls the rotation direction of said cutting tool to be switched from said reverse rotation direction to said normal rotation direction; said predetermined first condition is set by a setting unit based on a rotation angle or a rotation time when said driving unit (7, 13) drives said cutting tool in said normal rotation direction, and the satisfaction of the predetermined first condition defines a timing for switching driving to said reverse rotation direction, and wherein said predetermined second condition is set by the setting unit based on a reverse rotation angle or a reverse rotation time when said driving unit (7, 13) drives said cutting tool in said reverse rotation direction, and the satisfaction of the predetermined second condition defines a timing for switching driving to said normal rotation direction.