Member with flow passage and method for manufacturing the same

A method for manufacturing a member with flow passage in which a flow passage is provided in the member made of metal or alloy, comprising:

• a step of placing, on a base member made of metal or alloy, a plate-like member made of metal or alloy in a plate-like shape, including:
• two flat plate portions that are positioned at both widthwise ends and have main surfaces passing over one and the same plane;
• and a convex portion that is provided between the two flat plate portions and has a cross section shaped in a thickness direction so as to protrude with respect to the flat plate portions, and forming the flow passage, such that main surfaces of the flat plate portions opposite to a top of the convex portion are facing the base member;
• and
• a metal deposit layer formation step of forming a metal deposit layer by, while the plate-like member is placed on the base member, accelerating powder of metal or alloy together with a gas, and spraying and depositing the powder in a solid-phase state on a surface of the plate-like member at the top side of the convex portion and a surface of the base member.