To provide a method for analyzing oxygen in steel which does not require modification of the conventional oxygen analysis device and can be implemented in a short period of time.

A method for analyzing an oxygen concentration in molten steel in the midst of a refining step of stainless steel is provided, which includes: a sample preparation step of preparing an analysis sample 83 whose whole outer peripheral surface is made from a newly generated surface by dry-cutting an initial sample in air which is prepared by collecting the molten steel and cooling and solidifying it; a preheating step of reducing an oxide film of the surface of the analysis sample 83 by arranging the analysis sample 83 inside a crucible 7 made of black-lead and heating the analysis sample 83 at a preheating temperature of T-110(°C) or more and less than T(°C), where T(°C) denotes a temperature at which the analysis sample 83 is molten; and an analysis step of heating and melting the analysis sample 83 in an inert gas atmosphere and analyzing generated amount of the generated CO gas and/or the CO₂ gas.