An apparatus for producing a slush fluid wherein a liquid and solid particles are mixed together, comprising product tank (1) for storing the slush fluid (50) in its saturated condition; liquid nitrogen supply nozzle (10) provided at an upper part of the product tank (1); and compressor (15) for evacuating the interior of the product tank, which apparatus is adapted to spray a liquid in microparticulate form through the liquid nitrogen supply nozzle (10) into the product tank evacuated by the compressor (15) and to solidify the liquid particles by evaporative latent heat, thereby forming solid nitrogen (51). Preferably, the apparatus has a circulatory system for circulating the gas discharged from the product tank (1) by the compressor (15) to the liquid nitrogen supply nozzle (10), which circulatory system includes heat exchangers (13a, 13b) for heating the discharged gas to ordinary temperature by heat exchange; the compressor (15) for compressing the heated gas to thereby produce high-pressure ordinary-temperature gas; the heat exchangers (13a, 13b) for cooling the high-pressure ordinary-temperature gas to thereby produce high-pressure low-temperature gas; and auxiliary chilling refrigerator (17) and heat exchanger (16) for chilling the high-pressure low-temperature gas to thereby condense the same.