The present invention has a core which has a shape corresponding to the hollow section in the interior of a casting, and an outer mold which has a shape corresponding to the outer circumferential surface of the casting, wherein the outer mold comprises: a prime layer (101A) which is formed on the inner circumferential surface from a slurry film obtained by drying a mold slurry for precision casting; and a multi-layered back-up layer (105A) which is formed on the outside of the prime layer (101A) by forming multiple back-up layers (104) obtained by forming and drying slurry layers (102) formed from the mold slurry for precision casting, and stucco layers (103) obtained by attaching stucco particles as the stucco material on the slurry layers (102), the content of stucco particles by particle size distribution being 1 for fine particles having a particle size of 50 to 500 [mu]m, 1 to 16 for medium particles having a particle size of 0.5 to 2 mm, and 1 to 40 for coarse particles having a particle size of 2 to 4 mm.