Force sensor unit and robot arm including a wire cable routed from inside a casing to outside of the casing

A force sensor unit comprising:

• a force sensor;
• a casing having one end portion, another end portion, and a side portion located between the one end portion and the other end portion and housing the force sensor within a space surrounded by the one end portion, the other end portion, and the side portion;
• an attachment member having a first attachment portion that can be attached to a robot arm of a robot, and a second attachment portion detachably attached to the one end portion of the casing in a position different from that of the first attachment portion;
• a wiring cable connected to the force sensor and routed from inside the casing to outside of the casing, and a positioning portion on the first attachment portion and attached to the attachment member, the positing portion being configured to position the attachment member with respect to the robot arm, wherein a part of the wiring cable is provided along a circumferential direction of the side portion to reduce force sensor accuracy degradation by deformation or displacement of the wiring cable.