The invention provides a heat exchanger and a manufacturing method of the heat exchanger. The heat exchanger is provided with heat transfer tubes, heat transfer tube supporting parts, section steel and an integrally-formed tank body, wherein the heat transfer tubes are used for allowing first fluid to flow in the heat transfer tubes, the heat transfer tube supporting parts support the multiple heat transfer tubes, the multiple heat transfer tube supporting parts are connected through the section steel, and the integrally-formed tank body accommodates the heat transfer tubes, the heat transfertube supporting parts and the section steel and is used for allowing second fluid to flow in the tank body. The heat transfer tube supporting parts connected to the section steel can serve as a unit and are accommodated in the integrally-formed tank body, and manufacturing can be convenient. The manufacturing method of the heat exchanger comprises the following steps that the multiple heat transfer tube supporting parts are fixed to the section steel, the section steel with the multiple heat transfer tube supporting parts being fixed is accommodated in the integrally-formed tank body, the section steel with the heat transfer tube supporting parts being fixed is fixed to the tank body, and the heat transfer tubes are inserted in a plurality of heat transfer tube inserting through holes which are formed in the heat transfer tube supporting parts.