An operation information acquisition device comprising: an external detection device which is provided on an outer side of a main body frame of a sewing machine and detects a state change of an operating member that performs a periodic operation at a same cycle as an up-down movement operation of a sewing needle, and a control unit which executes processing or control for acquiring predetermined detection information, wherein the sewing machine includes: a main shaft motor; a main shaft which is rotationally driven by the main shaft motor; a needle bar and a sewing needle which reciprocate and move up and down by obtaining power from the main shaft; the operating member which performs a periodic operation at a same cycle as an up-down movement operation of the sewing needle ; and a photoelectronic sensor which detects the periodic operation of the operating member, wherein the control unit detects a rising edge (Eu) from an output of the photoelectronic sensor and monitors whether or not a next rising edge (Eu) is detected within the stop determination time, wherein in a case where the next rising edge (Eu) is detected within the stop determination time, the control unit determines that the main shaft motor and the main shaft are rotating, and continues to monitor whether or not the next rising edge (Eu) is detected within the stop determination time, wherein in a case where the next rising edge (Eu) is not detected within the stop determination time, the control unit determines that the main shaft motor and the main shaft are stopped, and wherein the operation information acquisition device acquires operation information based on detection result of the external detection device . an external detection device which is provided on an outer side of a main body frame of a sewing machine and detects a state change of an operating member that performs a periodic operation at a same cycle as an up-down movement operation of a sewing needle, and a control unit which executes processing or control for acquiring predetermined detection information, wherein the sewing machine includes: a main shaft motor; a main shaft which is rotationally driven by the main shaft motor; a needle bar and a sewing needle which reciprocate and move up and down by obtaining power from the main shaft; the operating member which performs a periodic operation at a same cycle as an up-down movement operation of the sewing needle ; and a photoelectronic sensor which detects the periodic operation of the operating member, a main shaft motor; a main shaft which is rotationally driven by the main shaft motor; a needle bar and a sewing needle which reciprocate and move up and down by obtaining power from the main shaft; the operating member which performs a periodic operation at a same cycle as an up-down movement operation of the sewing needle ; and a photoelectronic sensor which detects the periodic operation of the operating member, wherein the control unit detects a rising edge (Eu) from an output of the photoelectronic sensor and monitors whether or not a next rising edge (Eu) is detected within the stop determination time, wherein in a case where the next rising edge (Eu) is detected within the stop determination time, the control unit determines that the main shaft motor and the main shaft are rotating, and continues to monitor whether or not the next rising edge (Eu) is detected within the stop determination time, wherein in a case where the next rising edge (Eu) is not detected within the stop determination time, the control unit determines that the main shaft motor and the main shaft are stopped, and wherein the operation information acquisition device acquires operation information based on detection result of the external detection device . <EOS>