Manufacturing method for additive manufactured article and additive manufactured article

A method for manufacturing an additively-manufactured object, in which a plurality of linear weld beads obtained by melting and solidifying a weld wire with an arc are deposited on a base portion to build a built-up object, the method comprising:

• a support layer building step of forming a first support bead on the base portion having a vertical surface or a surface inclined from a deposition direction of the plurality of linear weld beads and building a support layer by depositing a plurality of second support beads in one direction on a side of the first support bead;
• and
• a depositing step of depositing a weld bead wider than the first support bead on the support layer along a direction orthogonal to a depositing direction of the plurality of second support beads, wherein,
• when the first support bead is formed to be inclined from a vertical direction in the support layer building step, a ratio H/W of a height H to a width W of the first support bead is set to 0.35 or more,
• the additively-manufactured object includes a wall portion having inner wall surfaces facing each other,
• the support layer is built by connecting a start edge and an end edge of the support layer to the inner wall surfaces facing each other, and
• the wall portion and the support layer forming a ceiling wall form a cavity portion.