PURPOSE: To provide an intake device which can improve the capability of warming up at a low temperature of an internal combustion engine and which prevents the intake efficiency from being deteriorated, even after the engine has been warmed up, so that it can ensure the high output performance.

CONSTITUTION: There are provided in an exhaust manifold 3: a recombustion space 7 for engine exhuast gases; dual inner and outer inside cylinders 8 and 9 formed with air layers at their backs; a heating portion 10 for heating the main and auxiliary heat receiving portions 4b and 5b of an intake manifold 2; an opening 8a for guiding the exhaust gases into the heating portion 10 of the outer inside cylinder 9; and a combination of a bolt 11 and a nut 12 for fixing the cylinders 8 and 9 to the exhaust manifold 3. With these constructions, the exhaust gases, which are heated by the cylinders 8 and 9 of the exhaust manifold 3, are kept free from being cooled directly by the heat of vaporization of the mixture. Since there is provided a water passage 6 contacting with the main and zuxiliary intake passages 4 and 5, the mixture passing through the two intake passages 4 and 5 can be prevented from being everheated so that the intake efficiency can be prevented from being deteriorated