Disclosed is a micro mixer which includes a mixing plate (14) with a first channel-forming section and a second channel-forming section. The first channel-forming section has a first channel formed for a first fluid to flow therethrough, while the second channel-forming section has a second channel formed for a second fluid to flow therethrough. Between the first channel-forming section and the second channel-forming section, there is provided a combined channel in which the first fluid and the second fluid merge with each other. The outlet of the first channel and the outlet of the second channel are opposed to each other with the combined channel disposed therebetween. The position of the outlet of the first channel facing the center axis of the combined channel is included in or the same as the position of the outlet of the second channel facing the center axis.