To obtain a batch-type experimental device that can efficiently proceed with an experiment and is suited for a super-critical water reaction experiment.

A super-critical water reaction experimental device 10 is a semi-batch-type super-critical water reaction experimental device, and consists of a reactor 12, a supply system 14 of hydrogen peroxide water, and an outflow system 16 of a reaction product. The reactor 12 is a pressure-resistant container that can be opened and closed freely, and is provided with an electrical resistance electrical heating element 18 being provided along a container wall, a temperature-controlling device 20 for controlling the strength of current flowing through the electrical resistance electrical heating element 18 so that temperature in the reactor 12 reaches a specific temperature. The supply system of hydrogen peroxide water is provided with a tank 24 for accommodating hydrogen peroxide water, a pump 25 for feeding the hydrogen peroxide water to the reactor 12, and a preheater 26 for preheating the hydrogen peroxide water to a specific temperature. The outflow system of the reaction product is provided with a water cooler 32, a self-operated pressure control valve 34, and a gas liquid separator 36 successively at a reaction product outflow pipe 31 where the reaction product flowing out of the reactor 12 flows. A TOC meter 38 for measuring the amount of organic matter in the reaction product is provided at the reaction product outflow pipe 31 at the downstream of a pressure control valve.