Arc welding method and solid wire

An arc welding method, comprising:

• performing welding by using a gas and a solid wire,
• wherein
• the gas contains Ar,
• the solid wire includes a steel core wire and a copper plating film formed on a surface of the steel core wire, and
• the copper plating film has an average grain diameter of 600 nm or less,
• wherein the welding is performed while controlling repeated feed of the solid wire in a forward and backward direction of the solid wire,
• wherein the solid wire comprises, in mass %:
• C:
• 0.15% or less;
• Si:
• 2.0% or less;
• Mn:
• 3.0% or less;
• and
• Cu:
• 0.5% or less.