Additive manufacturing and additive manufacturing method

An additive manufacturing device manufacturing an additively manufactured article by melting or sintering layered powder by partially applying energy to the powder, the additive manufacturing device comprising:

• a powder holding unit configured to hold the layered powder;
• a heating unit configured to heat the powder held by the powder holding unit by directing an energy beam from the heating unit to the powder holding unit via a region through which the energy beam passes defined therebetween;
• a reflection unit having a reflective film including a reflective surface disposed outside the region, the reflective surface configured to reflect radiant heat radiated from an object, including at least one of the powder and the additively manufactured article, toward the powder holding unit;
• and a reflective surface update unit configured to dispose a new reflective surface in the reflection unit by moving the reflective film.