A compound represented by the formula (I) is used as an active ingredient in a medicament for treatment or prevention of infectious diseases caused by protozoa or bacterium. X represents halogen, Z represents &mdash(CH2)m&mdash wherein m is an integer of 1-5, and R represents one of the following (i)-(v): (i) hydrogen n represents an integer of 0-5, R1s independently represent hydrogen, halogen, alkoxy having 1-5 carbon atoms or alkyl having 1-5 carbon atoms. R2s independently represent hydrogen, halogen, alkoxy having 1-5 carbon atoms or alkyl having 1-5 carbon atoms. (iv) alkyl having 1-5 carbon atoms, (v) hydroxyalkyl having 1-5 carbon atoms.
