The valve train V of an internal combustion engine E includes; a rocker arm 50, 60 for opening and closing the suction valve 13; a holding body 70 for holding the spring 77 to generate the bias force F3 for biasing the rocker arm 50 to the suction cam 21; and a drive shaft 81 for moving the supporting shaft 32, 33 of the rocker arm 50, 60 via the holder 30. The rocker arm 50 includes: an acting section 54 on which the bias force F3 of the spring 77 directly acts; a cam contact section 52 coming into contact with the suction cam 21. The holding body 70 provided integrally with the holder 30 moves following a position of the supporting shaft 32 which moves together with the holder 30. The spring 77 is arranged between the holding body 70 and the acting section 54, which are opposed to each other in the direction of the line of action of the bias force F3 and along the plane perpendicular to the rotary centerline L2 of the cam shaft 20.