Modified calcium aluminate compound and production method therefor

[Problem] Prior art does not disclose a method for modifying the surface of a calcium aluminate compound, much less a method for controlling the particle size of a calcium aluminate compound. The present invention provides a novel method for producing a calcium aluminate compound having a modified surface. [Solution] The present invention provides: a method for producing a modified calcium aluminate compound, which method is characterized by modifying the surface of the calcium aluminate compound by irradiating the calcium aluminate compound dispersed in an organic dispersion medium with a femtosecond laser; and a modified calcium aluminate compound which is characterized by being obtained by the method, and which has at least one of an OH group, a CO group, a CH group, and an NH group.