A controller includes a host command sensor suitable for generating a target ratio between first typed host commands and second typed host commands; an output command generator suitable for generating first and second typed output commands respectively corresponding to the first and second typed host commands; and an arbiter suitable for sequentially transmitting the first and second typed output commands from the output command queue to a channel, and generating a channel ratio between first and second typed output commands transmitted from the output command queue to the channel. The arbiter transmits one of the first and second typed output commands from the output command queue to the channel by comparing the channel ratio with the target ratio.