Adsorptions of antimicrobial poly(hexamethylenebiguanide hydrochloride) (PHMB) onto solid-supported lipid films composed of representative glycerophospholipids were analyzed by using surface plasmon resonance measurements. PHMB preferentially adsorbed onto negatively charged lipid films rather than zwitterionic lipid films. The adsorption amounts were drastically increased above the threshold PHMB concentration, which might be correlated with its antimicrobial effect.