Are arranged to form a transfer possible transport pipe 11, a powder flow passage (11d) at the top along the conveying pipe (11) by dividing the flow path cross-section and down by the powder by gravity fall into a predetermined inclination angle, the perforated plate (12 ) and, different from the perforated plate (provided on the lower side of 12), the perforated plate 12 is passed through a powder flow path (11d) to assist gas (g) fluidizing the inert gas supply passage (13 for supplying a), the powder flow path (11d) the deposition conditions to always monitor the situation in which the powder is deposited on the upper surface side of the porous plate 12 in and a monitoring device (20).