To provide a terminal plate with fins with which high heat radiation can stably be obtained and a flexible conductor using the terminal plate with fins.

The terminal plate 2 with fins are provided with a fin 1 on its external surface, 15 to 200 μm surface roughness of at least a flank 3 of the fin 1. The flexible conductor 8 has a flexible conductor material 7 connected to the terminal plate 2 with the fins. The flexible conductor has at least flanks 3 of the fins formed to proper surface roughness, so the flexible conductor 1 has superior heat radiating property, and also has its temperature rise when used for a terminal plate 2 of a flexible conductor to excellently maintain a state of connection with a flexible conductive material 7. The terminal plate 2 with the fins can speedily be manufactured by a water jet processing method with good productivity without using any postprocessing.