The invention provides a heat exchanger which comprises a first casing, a main shaft and a heating device, wherein the first casing is provided with a first accommodating cavity for accommodating materials; the main shaft penetrates through the first accommodating cavity rotationally and is provided with a second accommodating cavity, and a heat exchanger medium is arranged in the second accommodating cavity; and the heating device penetrates through the second accommodating cavity and rotates synchronously with the main shaft, and a first end of the heating device penetrates out of the main shaft and is connected with a power supply. The heat exchanger effectively solves the problem of uniform heat exchange, and the structure is simple.