In an engine valve train device in which a crankshaft sprocket 25b provided on a crankshaft 8 and an intermediate sprocket 38a disposed in the vicinity of camshafts 36, 37 are connected by means of a timing chain 40 and an intermediate gear 38b fixed to the intermediate sprocket 38a is made to mesh with camshaft gears 41, 42 fixed to the camshafts, the intermediate gear 38b is made smaller in diameter than the intermediate sprocket 38a and is disposed behind the intermediate sprocket 38, and furthermore, an inspection hole 38c is formed in the intermediate sprocket 38a for visualizing the meshing portion between the intermediate gear 38b and the camshafts gears 41, 42.