A liquid treatment apparatus according to an aspect of the present disclosure comprises a reactor and a plasma generator. The reactor includes an inner wall, a first space, and a second space. Each of the first space and a second space is capable of containing a liquid. The liquid is suppressed to move between the first space and the second space. The inner wall allows ions or electrons to move between the first space and the second space. The plasma generator includes a first electrode at least partially located in the first space, a second electrode at least partially located in the second space, and a power supply that applies AC or pulse voltage between the first electrode and the second electrode. The plasma generator produces plasma in the liquid.