An original plate material for a heat-exchanging plate fabricated by press working and a method for fabricating the original plate material are provided. An original plate material for a heat-exchanging plate is a flat plate material made of titanium on the surface of which convex parts and concave parts are formed, and the heat-exchanging plate is fabricated by press working the original plate material. The convex parts and the concave parts are formed in a manner such that the shape parameter defined by (Rz×L/P) is 12 μm or less, where Rz (μm) denotes the height of the convex parts, L (μm) denotes the width of the concave parts, and P (μm) denotes the pitch between neighboring convex parts.