A composition for delivering a bioactive material include a porous silica nanoparticle containing pores with an average pore diameter ranging from 1 nm to 100 nm, at least one of (i) a functional group which binds to the pore surface of the porous silica nanoparticle and gives the pore surface a negative charge or a positive charge, (ii) a ligand which binds to the pore surface of the porous silica nanoparticle and specifically binds to the bioactive material, and (iii) a combination of the functional group and the ligand, and a bioactive material having a size to be accommodated within the pores of the porous silica nanoparticle, the bioactive material bound to said at least one of the functional group and the ligand bound to the pore surface of the mesoporous silica nanoparticle and accommodated within the pores of the porous silica nanoparticle.