Abstract: The present invention provides a novel method for producing a calcium aluminate compound having a modified surface. The present invention provides: a method for producing a modified calcium aluminate compound characterized by irradiating a calcium aluminate compound dispersed in an organic dispersion medium with a femtosecond laser, thereby modifying the surface of the calcium aluminate compound; and a modified calcium aluminate compound characterized by being obtained by this method and having at least one of an OH group, a CO group, a CH group, and an NH group.