Eight sampling methods of adult black flies were compared at Shuzenji, Shizuoka Prefecture. Of these methods, those which could obtain a good number of flies were sweeping with nets, sticky ribbon hanging close to a stream and light traps set at a cowshed. Sweeping with nets and sticky traps were suitable for collecting males. However, light traps were more effective for mass collection of female Simulium aokii and S. bidentatum, both the blood-fed and unfed. S. aokii showed its maximum activity from just after sunset to midnight, S. bidentatum, on the other hand, showed its maximum activity after midnight until one or two hours before sunrise.