To obtain the subject composition persisting the antimicrobial function for a long time at a high temperature under a UV light-irradiating atmosphere and excellent in rubbery properties, flexural fatigue resistance, lubricity, conductivity, and the like, by adding a specific antimicrobial agent to a polyester block copolymer.

This antibacterial polyester elastomer composition comprises (A) 100 pts.wt. of a polyester block copolymer comprising a high melting point crystalline polymer segment (preferably polybutylene terephthalate) comprising crystalline aromatic polyester units and a low melting point polymer segment [preferably poly(tetramethylene oxide)glycol] comprising aliphatic polyether units and/or aliphatic polyester units, and (B) 0.1-20 pts.wt. of an antimicrobial agent produced by coating an amino acid metal compound (for example, silver N-stearoylglutamate) on the surfaces of inorganic particles. The particulate inorganic substance constituting the component B includes silica. The particle diameter of the inorganic substance is preferably 0.01-1 μm.