Surgical instrument device

A surgical device comprising:

• a surgical instrument;
• a device body configured to hold the surgical instrument;
• a force transmitting member formed in a shaft shape extending in an axial direction, wherein a first end portion of the force transmitting member in the axial direction is connected to the surgical instrument and a second end portion of the force transmitting member in the axial direction is supported by the device body, wherein the force transmitting member is configured to transmit a force between the surgical instrument and the device body;
• a distance change detector configured to detect a change in distance between two points away from each other in the axial direction on the force transmitting member based on a distance when no load is applied to the surgical instrument;
• and
• a processor configured to calculate a force applied from the surgical instrument or the device body to the force transmitting member based on the change in distance detected by the distance change detector,
• wherein the distance change detector comprises:
• a first displacement detector configured to detect a displacement of a distal end side point of the two points away from each other in the axial direction on the force transmitting member;
• and
• a second displacement detector configured to detect a displacement of a proximal end side point of the two points away from each other in the axial direction on the force transmitting member, and
• wherein the processor is configured to:
• convert the displacement of the distal end side point detected by the first displacement detector and the displacement of the proximal end side point detected by the second displacement detector into the displacements based on a position where no load is applied to the surgical instrument, and
• calculate the change in distance by calculating a difference between the displacement of the distal end side point and the displacement of the proximal end side point after the conversion.