PROBLEM TO BE SOLVED: To provide an antimicrobial agent containing a crystalline rutile type titanium oxide and exhibits an excellent antimicrobial activity in a bright place and a dark place.SOLUTION: An antimicrobial agent according to the present invention is an antimicrobial agent containing a titanium compound, and contains as the titanium compound a crystalline rutile type titanium oxide (excluding anion-doped titanium oxides and titanium oxides carrying a transition metal compound) having an average minor axis of 50 nm or less and an average aspect ratio (major axis/minor axis) of 1.5 or more, in an amount of larger than 50 wt.% based on the total titanium compounds contained in the antimicrobial agent. A rutile type titanium oxide having a crystal plane (110) and a crystal plane (111) and/or a rutile type titanium oxide having a crystal plane (110), a crystal plane (111), and a crystal plane (001) are/is preferable as the crystalline rutile type titanium oxide.SELECTED DRAWING: None
