N-(9-Anthrylmethyl)-1,4,7,10-tetraazacyclododecane (AC), which acts as an efficient fluorescent chemosensor for detection of pH and metal cations in aqueous solution, was covalently grafted on a NaX zeolite modified with octadecyl group (ZO). This grafted zeolite (ZOAC) is highly dispersed in aqueous solution and hardly precipitates even after 10 min standing, because of the modification with the hydrophobic octadecyl group. Consequently, even though ZOAC is employed for fluorescence measurement in heterogeneous systems, the same high fluorescence intensity as that for AC employed in homogeneous systems is obtained. ZOAC demonstrates as good a fluorescent response toward pH and metal cations as AC does. The metal cations coordinated by the AC group on ZOAC are removed easily by washing with aqueous HCl solution, and ZOAC can be reused for further measurement. The stability of the AC group on ZOAC is significantly higher than that of the homogeneous AC sensor under humid atmosphere, suggesting the potential utility of ZOAC for practical sensing of pH and metal cations in aqueous solution.