being sufficiently spaced from each other in the vertical direction with this arrangement both of them are seen in an overlapping state when viewed from above the multi cylinder internal combustion engine according to the present invention is constituted as described functions as described and has the following effects 1 the case containing the element of the oil filter is mounted to a side surface of the engine block therefore the removal and replacement of the filter case for replacement of the element can be easily performed without interference from the four exhaust pipes arranged on the front surface of the internal combustion engine 2 while the oil cooler mounted on the front surface of the engine is of the water cooled type it receives a running airflow directly thereon during movement of the vehicle so that an air cooling effect by the running airflow is also obtained with the result of a high oil cooling efficiency 3 the oil is supplied to a substantially central portion of the main gallery which extends in the left right direction and the oil pressure supplied to individual bearing portions dispersively arranged in the left right direction is made uniform and stable since the oil cooled by the oil cooler is supplied uniformly to the individual bearing portions the bearing portions are cooled uniformly 4 it is possible to appropriately maintain a weight balance in the left right direction of the internal combustion engine since the oil cooler and the balancer are both disposed at a front central portion of the internal combustion engine although the present invention has been described herein with respect to a limited number of.