A fiber bundle condensing device of a spinning machine comprising: a condensing unit including: a delivery bottom roller mounted on a rotary shaft and delivering a fiber bundle; a suction portion performing a suction operation on the fiber bundle; an air-permeable apron being rotated along the suction portion; and a delivery top roller being in contact with the delivery bottom roller through the air-permeable apron and rotating with the delivery bottom roller, the condensing unit condensing the fiber bundle, which have been drafted; a plurality of countershafts arranged in an axial direction of the countershafts and rotating the rotary shaft; a countershaft driving motor driving the countershafts; and a shaft coupling coupling the countershafts arranged side by side in the axial direction and integrally rotating with the countershafts, and the shaft coupling coupling the countershafts by fastening a coupling main body disposed over a first end portion of one countershaft and a second end portion of the other countershaft adjacent to the one countershaft with a bolt, characterized in that the fiber bundle condensing device further includes: a detected portion formed in at least one of the countershafts or the shaft coupling and detecting a rotational position of the at least one of the countershafts; a rotational position detector outputting rotational position information of the countershafts by detecting the detected portion; a controller to which the rotational position information output from the rotational position detector is input, the controller controlling the countershaft driving motor; and an operation unit outputting a stop command for stopping the driving of the countershaft driving motor to the controller, an operational range is defined as a range where a rotational position of the shaft coupling is located and the bolt used for the coupling main body is operable from a front of the fiber bundle condensing device, and the controller, when the stop command from the operation unit is input to the controller, controls the driving of the countershaft driving motor based on the rotational position information input from the rotational position detector such that the shaft coupling is located in the operation range at a time when the countershafts stop rotating. a condensing unit including: a delivery bottom roller mounted on a rotary shaft and delivering a fiber bundle; a suction portion performing a suction operation on the fiber bundle; an air-permeable apron being rotated along the suction portion; and a delivery top roller being in contact with the delivery bottom roller through the air-permeable apron and rotating with the delivery bottom roller, a delivery bottom roller mounted on a rotary shaft and delivering a fiber bundle; a suction portion performing a suction operation on the fiber bundle; an air-permeable apron being rotated along the suction portion; and a delivery top roller being in contact with the delivery bottom roller through the air-permeable apron and rotating with the delivery bottom roller, the condensing unit condensing the fiber bundle, which have been drafted; a plurality of countershafts arranged in an axial direction of the countershafts and rotating the rotary shaft; a countershaft driving motor driving the countershafts; and a shaft coupling coupling the countershafts arranged side by side in the axial direction and integrally rotating with the countershafts, and the shaft coupling coupling the countershafts by fastening a coupling main body disposed over a first end portion of one countershaft and a second end portion of the other countershaft adjacent to the one countershaft with a bolt, characterized in that the fiber bundle condensing device further includes: a detected portion formed in at least one of the countershafts or the shaft coupling and detecting a rotational position of the at least one of the countershafts; a rotational position detector outputting rotational position information of the countershafts by detecting the detected portion; a controller to which the rotational position information output from the rotational position detector is input, the controller controlling the countershaft driving motor; and an operation unit outputting a stop command for stopping the driving of the countershaft driving motor to the controller, a detected portion formed in at least one of the countershafts or the shaft coupling and detecting a rotational position of the at least one of the countershafts; a rotational position detector outputting rotational position information of the countershafts by detecting the detected portion; a controller to which the rotational position information output from the rotational position detector is input, the controller controlling the countershaft driving motor; and an operation unit outputting a stop command for stopping the driving of the countershaft driving motor to the controller, an operational range is defined as a range where a rotational position of the shaft coupling is located and the bolt used for the coupling main body is operable from a front of the fiber bundle condensing device, and the controller, when the stop command from the operation unit is input to the controller, controls the driving of the countershaft driving motor based on the rotational position information input from the rotational position detector such that the shaft coupling is located in the operation range at a time when the countershafts stop rotating.