To provide a molten steel level detection method and a molten steel level detection device for an arc furnace, melting and heating, or refining molten metal such as scrap iron.

In this molten steel level detection method for the arc furnace 1, an arc 7 is formed between at least one vertically moving electrode 6 and molten steel 5 formed by melting the molten metal such as the iron scrap to melt and heat, or refine the molten metal such as the iron scrap. In the molten steel level detection method, the electrode is contacted with the molten metal to bringing it in a short circuit state, a current is made to flow, the electrode is raised such that the current becomes a prescribed current to form the arc, and a molten steel level Hm is detected by calculation by an expression: Hm=He+(KWH2×Rc) from an electrode tip height He, an electrode consumption ratio Rc, and an electrode power use amount KWH2 in a refining period of a signal from a furnace situation decision device 28, when a current value of a current detector rapidly rises from zero when electricity carrying starts.