A crank chamber communication structure for a multi-cylinder internal combustion engine having a plurality of partition walls that are formed by a cylinder block and a crankcase, that are formed to support a crankshaft and to define a plurality of crank chambers that correspond to the plurality of cylinders, the structure including: a plurality of respective first communicating holes formed in the plurality of partition walls for communication between respective pairs of adjoining crank chambers separated by an interposed partition wall; and a second communicating hole that is formed at least either of the cylinder block or the crankcase, and that is interposed between a pair of non-adjoining crank chambers between which at least two partition walls among the plurality of partition walls are interposed for direct communication between the pair of non-adjoining crank chambers.