it is an object of the present invention to provide a rotation matching mechanism for an automatic clutch type transmission which makes it possible to obtain superior friction characteristics in a rotation matching braking device that synchronizes the gears of the transmission during up - shifting . the present invention provides an automatic clutch type transmission comprising a speed - change clutch which engages or disengages the driving force of the engine , a transmission which is connected to the speed - change clutch so as to transmit the abovementioned driving force , a shift lever which is used to shift the gears of the transmission , and a control device which automatically engages and disengages the abovementioned speed - change clutch as a result of the operation of the shift lever , wherein a rotation matching braking device is disposed on the input shaft of the transmission so that this braking device reduces the speed of rotation of the input shaft of the transmission during up - shifting and thus synchronizes the gear to which the shift is being made .