A cationically curable composition for dental use containing a cationic polymerization initiator (I) and cationically polymerizable monomers (II), the cationically polymerizable monomers (II) containing an oxetane compound and an epoxy compound or an alkenyl ether compound at a ratio of amounts that satisfy the conditions expressed by the following formula, (a.times.A):(b.times.B)=91:9 to 45:55 wherein A is a mol number of the oxetane compound, "a" is an average number of the oxetane functional group contained in one molecule of the oxetane compound, B is a mol number of the epoxy compound or the alkenyl ether compound, and "b" is an average number of the epoxy functional group contained in one molecule of the epoxy compound or an average number of the alkenyl ether functional group contained in one molecule of the alkenyl ether compound. The composition is not hindered by oxygen from being polymerized, cures quickly even without using a special polymerizable monomer or a particular polymerization initiator, little forms an unpolymerized layer on the surface even when polymerized and cured in a highly humid environment such as in the oral cavity, and is suited as a filling/restorative material for dental use.