A hydrogen reformer using exhaust gas, the hydrogen reformer comprising: a catalytic reaction unit for producing a reformed gas containing hydrogen when exhaust gas generated from an engine and fuel are supplied to the catalytic reaction unit; and a heat exchange chamber mounted on an outer surface of the catalytic reaction unit to provide heat necessary for an endothermic reaction of the catalytic reaction unit by using heat of the exhaust gas, wherein the catalyst reaction unit comprises: a housing having an inlet and an outlet in which the exhaust gas and the fuel are supplied into the housing through the inlet and a reformed gas containing hydrogen produced after the catalytic reaction is discharged through the outlet out of the housing; and a metal catalyst carrier mounted in the housing to react with the exhaust gas and the fuel thereby producing the reformed gas, characterized in that a heat exchange unit is provided in the heat exchange chamber to increase a heat exchange area between the exhaust gas and the catalytic reaction unit and extend the time for which the exhaust gas stay to improve the heat exchange performance, and the heat exchange unit is formed of a heat exchange plate mounted so as to be wound on the outer surface of the housing at certain intervals to thus partition the inside of the heat exchange chamber into a plurality of spaces and allow the exhaust gas to pass through the outer surface of the housing while being rotated around the outer surface of the housing. a catalytic reaction unit for producing a reformed gas containing hydrogen when exhaust gas generated from an engine and fuel are supplied to the catalytic reaction unit; and a heat exchange chamber mounted on an outer surface of the catalytic reaction unit to provide heat necessary for an endothermic reaction of the catalytic reaction unit by using heat of the exhaust gas, wherein the catalyst reaction unit comprises: a housing having an inlet and an outlet in which the exhaust gas and the fuel are supplied into the housing through the inlet and a reformed gas containing hydrogen produced after the catalytic reaction is discharged through the outlet out of the housing; and a metal catalyst carrier mounted in the housing to react with the exhaust gas and the fuel thereby producing the reformed gas, characterized in that a heat exchange unit is provided in the heat exchange chamber to increase a heat exchange area between the exhaust gas and the catalytic reaction unit and extend the time for which the exhaust gas stay to improve the heat exchange performance, and the heat exchange unit is formed of a heat exchange plate mounted so as to be wound on the outer surface of the housing at certain intervals to thus partition the inside of the heat exchange chamber into a plurality of spaces and allow the exhaust gas to pass through the outer surface of the housing while being rotated around the outer surface of the housing. a housing having an inlet and an outlet in which the exhaust gas and the fuel are supplied into the housing through the inlet and a reformed gas containing hydrogen produced after the catalytic reaction is discharged through the outlet out of the housing; and a metal catalyst carrier mounted in the housing to react with the exhaust gas and the fuel thereby producing the reformed gas, characterized in that a heat exchange unit is provided in the heat exchange chamber to increase a heat exchange area between the exhaust gas and the catalytic reaction unit and extend the time for which the exhaust gas stay to improve the heat exchange performance, and the heat exchange unit is formed of a heat exchange plate mounted so as to be wound on the outer surface of the housing at certain intervals to thus partition the inside of the heat exchange chamber into a plurality of spaces and allow the exhaust gas to pass through the outer surface of the housing while being rotated around the outer surface of the housing.