This powder transport device comprises: transport pipe (11) that can transport powder by way of gravity by having a prescribed angle of inclination; a porous plate (12) that is disposed along the transport pipe (11) so as to divide a line cross section into a top section and bottom section and form a powder line (11d) in the top section; an inert gas supply line for fluidization (13) that is provided under the porous plate (12) and supplies an assist gas (g) to the powder line (11d) through the porous plate (12); and a deposit status monitoring device (20) that constantly monitors the state of the powder deposited on the top face side of the porous plate (12) in the powder line (11d).