A driving force transmission apparatus includes: a meshing member that switches two rotating members between a coupled state and an uncoupled state; a piston member with a plurality of locked portions formed along a circumferential direction; an armature that moves the piston member forward and backward between a first position where the armature presses the piston member in an axial direction and a second position where the armature does not press the piston member; a biasing member that biases the piston member in the opposite direction from the pressing direction of the armature; and a locking member that locks the locked portions. The piston member has a mechanism that mitigates a possible shock when the locking member comes into abutting contact with an abutting contact surface of a first locked portion.