An EGR cooler in the disclosure includes: a gas path configured to allow an EGR gas to flow; a refrigerant path configured to perform heat exchange between the EGR gas circulating along the gas path and a refrigerant; an exothermic body containing portion configured such that an exothermic body to generate heat by adsorbing a predetermined working gas is contained within the EGR cooler and at least a part of the exothermic body contacts with a wall surface of the gas path; a working gas tank in which the working gas is stored; and a gas moving apparatus configured to move the working gas stored in the working gas tank, from the working gas tank to the exothermic body containing portion.