Double clutch assembly comprising: a cover casing receiving a driving force from an engine to rotate; a diaphragm spring installed deformable in an axis direction with respect to the cover casing to induce displacement in the axis direction of the cover casing; a centre plate connected to the cover casing and installed to idle with respect to an input shaft of a transmission; an auxiliary cover casing coupled to the centre plate to form a support point of the diaphragm spring together with the cover casing; a pressure plate selectively connected to a disc of the centre plate when the diaphragm spring is contracted; an auxiliary pressure plate coupled to the centre plate and installed to idle with respect to the input shaft of the transmission; a disc installed between the centre plate and the pressure plate, the disc comprising a hub to be coupled to the input shaft of the transmission to provide the driving force transmitted through the pressure plate to the input shaft of the transmission; an auxiliary disc installed between the centre plate and the auxiliary pressure plate, the auxiliary disc comprising a hub to be coupled to the input shaft of the transmission to provide the driving force transmitted through the auxiliary pressure plate to the input shaft of the transmission; and a guide plate fixed to the auxiliary cover casing and fitted into at least one groove of a cutting groove of the diaphragm spring and a cutting groove of the auxiliary diaphragm spring, the guide plate comprising a main body having a coupling hole for the coupling with the auxiliary cover casing; and a protrusion protruding from the main body in the radius direction and inserted into the cutting groove of the diaphragm spring, characterised in that the main body is constituted by divided pieces that have an outer appearance having a ring shape as a whole by combining the pieces, each of which has an arc shape corresponding to that of the corresponding portion of the auxiliary cover casing fixing the auxiliary cover casing with the guide plate, with each other. a cover casing receiving a driving force from an engine to rotate; a diaphragm spring installed deformable in an axis direction with respect to the cover casing to induce displacement in the axis direction of the cover casing; a centre plate connected to the cover casing and installed to idle with respect to an input shaft of a transmission; an auxiliary cover casing coupled to the centre plate to form a support point of the diaphragm spring together with the cover casing; a pressure plate selectively connected to a disc of the centre plate when the diaphragm spring is contracted; an auxiliary pressure plate coupled to the centre plate and installed to idle with respect to the input shaft of the transmission; a disc installed between the centre plate and the pressure plate, the disc comprising a hub to be coupled to the input shaft of the transmission to provide the driving force transmitted through the pressure plate to the input shaft of the transmission; an auxiliary disc installed between the centre plate and the auxiliary pressure plate, the auxiliary disc comprising a hub to be coupled to the input shaft of the transmission to provide the driving force transmitted through the auxiliary pressure plate to the input shaft of the transmission; and a guide plate fixed to the auxiliary cover casing and fitted into at least one groove of a cutting groove of the diaphragm spring and a cutting groove of the auxiliary diaphragm spring, the guide plate comprising a main body having a coupling hole for the coupling with the auxiliary cover casing; and a protrusion protruding from the main body in the radius direction and inserted into the cutting groove of the diaphragm spring, characterised in that the main body is constituted by divided pieces that have an outer appearance having a ring shape as a whole by combining the pieces, each of which has an arc shape corresponding to that of the corresponding portion of the auxiliary cover casing fixing the auxiliary cover casing with the guide plate, with each other.