be formed with a hole in the bearing main body 15 by a drill or the like because the illustrated engine is less likely to produce the striking noise generated from the engaging part of the exhaust valve lifter 5 it is possible to install a metal plate exhaust manifold 2 therefore the engine can be made lighter and the thermal capacity of the exhaust manifold 2 can be decreased in comparison with an engine using a cast exhaust manifold the decreased thermal capacity results in less temperature drop of the exhaust gas and it is possible for the catalytic converter 3 to reach the activation temperature more quickly after an engine start the embodiment above shows an example where the auxiliary oil passage 24 is formed in the bearing main body 15 of the cylinder head 1 however the oil collecting part 21 and the first and second concave ditches 22 and 23 can be formed in the cam cap 17 when this structure is used because it is not necessary to consider the attachment direction when the cam cap 17 is attached to the bearing main body 15 by forming the oil collecting part 21 and the first and second concave ditches 22 and 23 on both sides in the longitudinal direction of the cam cap 17 assembly can be done easily even when this structure is used the guide wall 25 preferably is formed on the downstream side in the direction of the rotation of the exhaust camshaft 6 as described in the above embodiment when the structure in which the oil collecting part 21 and the first and second concave ditches 22 and 23 are formed in the cam cap 17 is used the likelihood.