A heating apparatus for a cabin of a construction equipment in which hot air ejected from an oil cooler is used for heating in the winter while it is ejected out in the summer, to maximize cooling or heating efficiency of the cabin of the construction equipment. The heating apparatus for a cabin of a construction equipment includes a duct ejecting air ejected from an oil cooler provided inside an automotive body at the rear of the cabin to the outside of the automotive body, and a switching unit provided in the duct to open and close an air vent in the duct, guiding the air inside the duct to the rear of the cabin if it is opened. The heating apparatus is automatically operated depending on its peripheral temperature condition to maximize cooling or heating efficiency of the cabin.