Manufacturing method of copper bonded part

A manufacturing method of a copper bonded part in which a first copper member and a second copper member are bonded together,

• the first copper member and the second copper member being made of copper or a copper alloy,
• at least one of the first copper member and the second copper member including a copper porous body made of copper or a copper alloy,
• the manufacturing method comprising:
• a bonding material disposing step of disposing a bonding material between the first copper member and the second copper member;
• and
• a reduction sintering step of heating and holding the first copper member, the second copper member, and the bonding material in a reducing atmosphere in a range of 600° C. or higher and 1,050° C. or lower,
• wherein the bonding material contains a copper oxide or a mixture of metallic copper and the copper oxide in which a molar ratio between copper and oxygen is set to be in a range (Cu:O) of 1:0.3 to 1.0, and has at least one of copper oxide powder or metallic copper powder,
• an average particle diameter D of the copper oxide powder or the metallic copper powder is in a range of 0.05×Dp≤D≤2×Dp with respect to an average pore diameter Dp of the copper porous body, and
• a bonding layer made of metallic copper is formed between the first copper member and the second copper member.