A dental treatment apparatus comprising: a handpiece comprising a head that is configured to hold a cutting tool; a drive unit (7, 13) capable of forward rotation drive in which a cutting tool held by the head of the handpiece is rotated in a cutting direction and reverse rotation drive in which the cutting tool is rotated in a non-cutting direction; a control unit configured to control the drive unit (7, 13) configured to drive the cutting tool; a load detector configured to detect a load applied to the cutting tool; and a cumulative rotation amount calculator configured to calculate a cumulative amount of rotation which is a sum of angles of rotation of the cutting tool driven with the forward rotation drive and of angles of rotation of the cutting tool driven with the reverse rotation drive, wherein angles of rotation in forward rotation drive are represented by positive values and angles of rotation in reverse rotation drive are represented by negative values; the control unit being configured to continue drive of the cutting tool in the forward rotation drive until reaching a predetermined first amount of rotation regardless of a result obtained by the load detector, if the load applied to the cutting tool and detected by the load detector in the forward rotation drive of the cutting tool up to the first amount of rotation is equal to or greater than a reference load, switch drive of the cutting tool to the reverse rotation drive until reaching a predetermined second amount of rotation, and if not repeat forward rotation drive by the predetermined first amount of rotation regardless of a result obtained by the load detector, and when the cumulative amount of rotation calculated by the cumulative rotation amount calculator is equal to or greater than a reference amount of rotation while drive with the forward rotation drive and the reverse rotation drive being repeated is carried out, carry out predetermined control for eliminating twist of the cutting tool. a handpiece comprising a head that is configured to hold a cutting tool; a drive unit (7, 13) capable of forward rotation drive in which a cutting tool held by the head of the handpiece is rotated in a cutting direction and reverse rotation drive in which the cutting tool is rotated in a non-cutting direction; a control unit configured to control the drive unit (7, 13) configured to drive the cutting tool; a load detector configured to detect a load applied to the cutting tool; and a cumulative rotation amount calculator configured to calculate a cumulative amount of rotation which is a sum of angles of rotation of the cutting tool driven with the forward rotation drive and of angles of rotation of the cutting tool driven with the reverse rotation drive, wherein angles of rotation in forward rotation drive are represented by positive values and angles of rotation in reverse rotation drive are represented by negative values; the control unit being configured to continue drive of the cutting tool in the forward rotation drive until reaching a predetermined first amount of rotation regardless of a result obtained by the load detector, if the load applied to the cutting tool and detected by the load detector in the forward rotation drive of the cutting tool up to the first amount of rotation is equal to or greater than a reference load, switch drive of the cutting tool to the reverse rotation drive until reaching a predetermined second amount of rotation, and if not repeat forward rotation drive by the predetermined first amount of rotation regardless of a result obtained by the load detector, and when the cumulative amount of rotation calculated by the cumulative rotation amount calculator is equal to or greater than a reference amount of rotation while drive with the forward rotation drive and the reverse rotation drive being repeated is carried out, carry out predetermined control for eliminating twist of the cutting tool. continue drive of the cutting tool in the forward rotation drive until reaching a predetermined first amount of rotation regardless of a result obtained by the load detector, if the load applied to the cutting tool and detected by the load detector in the forward rotation drive of the cutting tool up to the first amount of rotation is equal to or greater than a reference load, switch drive of the cutting tool to the reverse rotation drive until reaching a predetermined second amount of rotation, and if not repeat forward rotation drive by the predetermined first amount of rotation regardless of a result obtained by the load detector, and when the cumulative amount of rotation calculated by the cumulative rotation amount calculator is equal to or greater than a reference amount of rotation while drive with the forward rotation drive and the reverse rotation drive being repeated is carried out, carry out predetermined control for eliminating twist of the cutting tool.