A novel antibacterial agent for Gram-positive bacteria which disregards the drug-resistant mechanisms of bacteria is disclosed. The antibacterial agent contains as an effective ingredient particles having a particle diameter of not more than 5 µm, which particles are adhesive to cell wall of Gram-positive bacteria and not adhesive to mammalian cell membrane and substantially do not contain an active antibacterial ingredient effective against Gram-positive bacteria. By the antibacterial agent according to the present invention, the growth of the multidrug-resistant Gram-positive bacteria such as MRSA and VRE can be inhibited, as well as the occurrence of novel multidrug-resistant bacteria, which is a big problem in use of antibiotics, can be avoided.
