Development of materials (antibacterial materials) that adsorb and remove microbial cells in aqueous solution for a long period of time by binding antibacterial substances such as polyethyleneimine and polyvalent cationic antibacterial agents in a stable form to water-insoluble carriers. A conjugate obtained by binding polyethyleneimine having a molecular weight of 200 to 1,000,000 to a water-insoluble carrier, and the conjugate provides a microbial cell adsorption medium for adsorbing microbial cells and a method for producing the same. In addition, a conjugate obtained by binding a polyvalent cationic antibacterial agent to a water-insoluble carrier, and the conjugate provides a microbial cell adsorption medium for adsorbing microbial cells and a method for producing the same.ポリエチレンイミンや多価カチオン性抗菌剤といった抗菌物質を水不溶性担体に安定な形で結合させ、水溶液中の微生物菌体を長期間、連続して吸着除去する資材(抗菌資材)の開発を図る。 分子量200~1000,000のポリエチレンイミンを水不溶性担体に結合させた結合体であって、前記結合体は微生物菌体を吸着する微生物菌体吸着媒とその製造方法を提供する。また、多価カチオン性抗菌剤を水不溶性担体に結合させた結合体であって、前記結合体は微生物菌体を吸着する微生物菌体吸着媒とその製造方法を提供する。