To provide a method for manufacturing a pattern for investment casting, and a casting core with which the maintenance of a spacial relation of the core and the drawing of a die and the pattern are improved.

A core assembly 60 is composed of a supplying core and a refractory metal core. The refractory metal core is provided with tabs 110, 112 for forming the outlet of circulation in the pattern. A die assembly 200 is provided with the dies 202, 204 and inserting parts 210A-E. Firstly, the dies are assembled around the core 60, and the inserting parts are inserted in the directions 550A-E. After pouring wax 222, the inserting parts 210A, B for die 202 are taken out and the die 202 is drawn out in the direction 541 and taken out from the die 204. During the above process, the pattern is kept under state of engaging with the die 204, with backlocking of the inserting parts 210C-E to the refractory metal core. Thereafter, the remained inserting parts 210C-E are drawn out and the pattern is taken out from the die 204.