A rotation transmitting member adapted to be attached to an end of one shaft of an input shaft and an output shaft both rotating around an axis, and to engage with a hub attached to an end of the other shaft of the input shaft and the output shaft, wherein the rotation transmitting member has a shaft hole into which the one shaft is to be inserted; characterized in that the rotation transmitting member further comprises: a first plate which is placed on the side of the one shaft; and a second plate, which is placed on the side of the other shaft and which has an elastic coefficient different from the one of the first plate; wherein a hole passing through the first plate and a hole passing through the second plate in the direction of the axis of the shaft form together the shaft hole: wherein in the hole formed in the plate having the larger elastic coefficient out of the first and second plates, an inner wall area of the shaft hole which is opposed to a flat surface on an outer periphery surface of an end portion of the one shaft is formed with two inclined surfaces inclined inward in a radial direction of the shaft hole from both end portions to a center of the area, along an axis of the one shaft, such that the end portion of the one shaft can be fitted into the hole with a clearance; and wherein in the hole formed in the plate having the smaller elastic coefficient out of the first and second plates, a flat surface is formed on an inner wall opposed to the flat surface of the end portion, such that the end portion can be fitted into the hole such that there is no clearance between the flat surface of the inner wall and the flat surface of the end portion. a first plate which is placed on the side of the one shaft; and a second plate, which is placed on the side of the other shaft and which has an elastic coefficient different from the one of the first plate; wherein a hole passing through the first plate and a hole passing through the second plate in the direction of the axis of the shaft form together the shaft hole: wherein in the hole formed in the plate having the larger elastic coefficient out of the first and second plates, an inner wall area of the shaft hole which is opposed to a flat surface on an outer periphery surface of an end portion of the one shaft is formed with two inclined surfaces inclined inward in a radial direction of the shaft hole from both end portions to a center of the area, along an axis of the one shaft, such that the end portion of the one shaft can be fitted into the hole with a clearance; and wherein in the hole formed in the plate having the smaller elastic coefficient out of the first and second plates, a flat surface is formed on an inner wall opposed to the flat surface of the end portion, such that the end portion can be fitted into the hole such that there is no clearance between the flat surface of the inner wall and the flat surface of the end portion. wherein in the hole formed in the plate having the larger elastic coefficient out of the first and second plates, an inner wall area of the shaft hole which is opposed to a flat surface on an outer periphery surface of an end portion of the one shaft is formed with two inclined surfaces inclined inward in a radial direction of the shaft hole from both end portions to a center of the area, along an axis of the one shaft, such that the end portion of the one shaft can be fitted into the hole with a clearance; and wherein in the hole formed in the plate having the smaller elastic coefficient out of the first and second plates, a flat surface is formed on an inner wall opposed to the flat surface of the end portion, such that the end portion can be fitted into the hole such that there is no clearance between the flat surface of the inner wall and the flat surface of the end portion.