アブストラクト：
Galactic-scale molecular gas outflow is an important phenomena as a feedback mechanism in galaxy evolution scenario. We report ALMA detection of dense molecular gas outflow traced by HCN and HCO+ from the merging galaxy NGC3256. We find that the dense gas fraction increases and low-J CO ratio decreases towards the largest velocity offset. This difference can be explained by the existence of a two-phase (diffuse component traced by CO and clumpy component traced by dense gas tracers) outflow, which is one of the signatures of the positive feedback.