In an internal combustion engine having a pair of balancer shafts (53, 54), an engine torque is transmitted from a crank gear (28) to an oil pump gear (74) on a drive shaft (73) of an oil pump (71) via a first idler gear (84) and the first balancer shaft gear (64). The engine torque is also transmitted to a fuel pump (72) from the crank gear to a fuel pump gear (78) via the first idler gear and a second idler gear (86), and to the second balancer shaft gear (67) via the first idler gear and second idler gear. Alternatively, the engine torque may be transmitted to the fuel pump from the crank gear to the fuel pump gear via the first idler gear, second balancer shaft gear and second idler gear. As the oil pump gear is actuated by the crank gear via the first idler gear, the oil pump gear is not subjected to the loading caused by the balancer shaft, and hence can be made of a compact and light-weight gear. Furthermore, this allows the various gears to be arranged in an efficient (in terms of the overall weight for the given mechanical strength requirements) and compact manner.