Externally added charge control agents (EA-CCAs) were prepared by means of a coacervation process. Spherical silica particles of 100 nm average diameter were coated with two kinds of charge control agents (CCAs); one was a polymer type P-1 and the other was a low molecular weight type P-2. Both of CCAs made remarkable contribution to toner charge. In a concentration range up to 0.2 μmol/g of CCA on toner, toner charge increased. From the relationship between the amount of EA-CCA on the toner and the tribocharge, P-2 was found more effective than P-1. It was estimated that 0.7 mol% of P-1 repeating units and 1.3 mol% of P-2 molecules contributed to toner charge, respectively. Calculation of the surface coverage of P-2 on spherical silica particles showed that the efficient concentration region of charge agreed with the 100% of surface coverage. The P-2 concentration was 0.02 μmol/g based on toner. This means that the CCA molecule has a great effect on tribocharge in small concentration.