A heat exchanger includes a heat exchanger case, a bottom member (90B) attached to one end of the heat exchanger case, and a plurality of heat transfer pipes (a pipe group 80) loaded in the inside of the heat exchanger case, in which blood flows from one end through the bottom member (90B). The bottom member (90B) has an annular wall (93), a bottom surface (96), and a blood inlet port (98). The bottom surface (96) is opposed to one end of the heat transfer pipe. The bottom surface (96) includes a groove portion (96c) and a raised bottom portion (96a, 96b) provided on each of opposing end sides of the groove portion (96c). The raised bottom portion (96a, 96b) is inclined such that a distance (H2) between the raised bottom portion (96a, 96b) on a side where the blood inlet port (98) is provided and one end of the heat transfer pipe is smaller than a distance (H1) between the raised bottom portion (96a, 96b) opposite to the side where the blood inlet port (98) is provided and one end of the heat transfer pipe. Flow of blood to each heat transfer pipe (pipe group 80) becomes uniform and high heat exchange performance can be obtained.
