To provide a compact, easily handling and inexpensive two-liquid mixer, capable of preserving an undiluted solution over a long period in a sealed container without being exposed to the atmosphere, and capable of mixing, discharging, diluting and spraying a mixed liquid in a single operation by being connected to tap water in use.

The two-liquid mixer is provided so as to be sealably fixable to a header 20 by a screw 22 of the container 28 and a gasket 23, and the header 20 and a mixer body 1 are each connected by valve means 14, and a valve mechanism 2 composed of a ball and a spring is arranged on a lever 15 of the valve means 14, and the ball 31 is attached/detached to and from a valve seat 24 formed in the header 20 by interlocking with operation of the valve means 14, and a space 34 of the container 28 can be switched to the atmosphere from tight seal.