Transmission and measuring instrument

A transmission comprising:

• a bearing comprising an inner race, an outer race, and a plurality of rolling elements housed between the inner race and the outer race, the outer race not being subject to spring-induced pressure;
• an input shaft which has an insertion portion inserted into the inner race and is rotated about a rotation axis of the rolling bearing and rotates the inner race;
• a holding member which comprises a holding portion held by the rolling elements and is rotated about the rotation axis in accordance with rolling of the rolling elements;
• an output shaft which is connected to the holding member and is rotated about the rotation axis in accordance with rotation of the holding member;
• a clamping mechanism connected to a supporting member, the clamping mechanism including a pressing member and a spring member, the clamping mechanism exerting pressure on an outer end of the output shaft;
• a ball bearing being opposed to the output shaft in a radial direction, the ball bearing having a rotational axis substantially parallel to the rotational axis of the output shaft, the ball bearing and the output shaft clamping a feeding tape which connects the transmission to the feeding tape,
• wherein when the output shaft is rotated, the ball bearing is also rotated, thereby moving a beam supporting member along a direction perpendicular to the rotational axis of the output shaft.