A driving force transmission apparatus , comprising: a first rotary member , that is to be rotated by a driving source of a vehicle; a second rotary member that is arranged along a rotation axis (O) of the first rotary member so as to be rotatable relative to the first rotary member ; a first clutch that is interposed between the second rotary member and the first rotary member , and that couples the first rotary member and the second rotary member to each other such that the first rotary member and the second rotary member are disengageable from each other; a second clutch that is arranged next to the first clutch along the rotation axis; a first cam mechanism that converts rotational force from the first rotary member into first cam thrust force (P1) that is used as clutch force of the first clutch when the first cam mechanism is actuated through clutch action of the second clutch ; and a second cam mechanism that generates second cam thrust force (P2) for reducing an interval between clutch plates of the first clutch , wherein the second cam mechanism has an input cam member that rotates upon receiving rotational force that is used as actuating force for the input cam member to be received from a cam actuating driving source , and an output cam member that generates the second cam thrust force (P2) between the output cam member and the input cam member and outputs the second cam thrust force (P2), characterized in that the second cam mechanism is actuatable prior to conversion of the rotational force from the first rotary member into the first cam thrust force (P1) by the first cam mechanism , and in that the cam actuating driving source is different from the driving source . a first rotary member , that is to be rotated by a driving source of a vehicle; a second rotary member that is arranged along a rotation axis (O) of the first rotary member so as to be rotatable relative to the first rotary member ; a first clutch that is interposed between the second rotary member and the first rotary member , and that couples the first rotary member and the second rotary member to each other such that the first rotary member and the second rotary member are disengageable from each other; a second clutch that is arranged next to the first clutch along the rotation axis; a first cam mechanism that converts rotational force from the first rotary member into first cam thrust force (P1) that is used as clutch force of the first clutch when the first cam mechanism is actuated through clutch action of the second clutch ; and a second cam mechanism that generates second cam thrust force (P2) for reducing an interval between clutch plates of the first clutch , wherein the second cam mechanism has an input cam member that rotates upon receiving rotational force that is used as actuating force for the input cam member to be received from a cam actuating driving source , and an output cam member that generates the second cam thrust force (P2) between the output cam member and the input cam member and outputs the second cam thrust force (P2), an input cam member that rotates upon receiving rotational force that is used as actuating force for the input cam member to be received from a cam actuating driving source , and an output cam member that generates the second cam thrust force (P2) between the output cam member and the input cam member and outputs the second cam thrust force (P2), characterized in that the second cam mechanism is actuatable prior to conversion of the rotational force from the first rotary member into the first cam thrust force (P1) by the first cam mechanism , and in that the cam actuating driving source is different from the driving source . <EOS>