Provided is a method of decomposing a crosslinked rubber that includes: a first decomposition step of decomposing a crosslinked rubber containing a diene rubber, using a catalyst represented by the following general formula (1), (2), or (3), where M is ruthenium, molybdenum, etc., X.sup.1, X.sup.2, L.sup.1, L.sup.2, and L.sup.3 each independently represent a ligand, R.sup.1, R.sup.2, and R.sup.3 each independently represent hydrogen, an alkyl group, a cycloalkyl group, an alkenyl group, an alkynyl group, an aryl group, etc. (these groups may be substituted by one or more alkyl groups, halogens, alkoxy groups, etc.), L.sup.1 and L.sup.2, R.sup.1 and R.sup.2, and L.sup.1 and R.sup.1 may respectively bond with each other to form rings; and a second decomposition step of pyrolyzing a decomposition product obtained by the first decomposition step under an inert gas atmosphere and in the absence of a catalyst at a temperature of 600 C. to 950 C.

##STR00001##