PURPOSE: To provide a speed differential sensitive coupling that has checked a transfer torque variation in and around the closure of an orifice to the minimum without improving the accuracy of finishing, in this coupling generating a transfer torque due to outflow regulation by the orifice at the time of relative rotation between both first and second rotary members.

CONSTITUTION: As an orifice member, it is divided into two parts, a first orifice 72 where six orifice ports 72b in response to the number of a cylinder chamber 60 are formed up to an end face 72c at the side of an accumulator chamber, and a second orifice member 73 where a contact surface 73b with this accumulator chamber side end face 72c and an end face 73c adjoining an accumulator chamber 90 both are formed. In addition, the accumulator chamber side end face 72c in an assembled state due to the press-in of both first and second orifice members 72 and 73 and an orifice member abutting surface B made by the contact surface 73b both are set up in parallel with an end face 120a of a spool 120.