To provide a blow nozzle or the like capable of restraining useless consumption of dry sand and capable of improving productivity.

A blow head device 1 is provided so as to come into contact with and separate from a die 8, and is provided with a blow head 2 and a blow plate 3. A blow nozzle 7 having a nozzle main body 15 and a plug body 16 is provided in the opening part of the blow plate 3. A forming cavity 13 is provided in the die 8, and an opening nozzle housing part 14 is formed in the cavity 13. In the case of forming, the blow head device 1 is arranged closely to the die 8, the blow nozzle 7 is housed into the nozzle housing part 14 so that the opening part α of the cavity 13 and the opening part of the nozzle main body 15 form nearly one surface, and shell sand 4 is filled. After forming, the shell sand 4 does not exist in the nozzle housing part 14 of the die 8.