To miniaturize a crankcase main body and a side cover by the rational arrangement of a governor gear and a governor arm shaft.

In this V-type internal combustion engine, a support boss 38 is formed on the front surface of a skirt part of a cylinder block 2 of the innermost bank out of first and second banks B1, B2 in viewing a crankcase main body 1A from a side cover side. A governor arm shaft 40 is supported on the support boss 38, a governor gear 37 on the outer periphery of a centrifugal governor 31 supported on the side cover is engaged with a drive gear 18 of a timing transmission device 16, and the governor arm shaft 40 is arranged between a crank weight and a driven gear 19 of the timing transmission device 16.