Faujasite type zeolite synthesized from kaolin minerals was cation-exchanged and the catalytic activities of <Na-, Zn-, La-, and hydrogen-faujasites for 1-butene cracking and isomerization were studied. $1-Butene{ ightarrow}2-butene$ took place readily even on zeolites having no strong acid sites. The order of activity for isobutene formation was La > H > Zn > Na-faujasite, La-faujasite showing much higher activity. The same trend was observed for propylene formation except that both La-and H-faujasite showed comparable activity. The results seem to indicate that the activities for 1-buten cracking and isomerization on zeolite are directly related to the strength and concentration of the acid sites on zeolites.