PURPOSE: To provide a packed box lunch feed system capable of serving at least two kinds of cooked foods in a box lunch and feeding the box lunch from a cooking maker side to a user side.

CONSTITUTION: The objective heat sterilizing system of packaged box lunch comprises an airtight packaging process 7 for airtightly packaging a box lunch containing a cooked food through an airtightly packaging means such as packaging film, a heat sterilizing treatment process 8 for subjecting an airtightly packaged body to heat sterilization treatment under a preliminarily set heating temperature, a process 9 transporting at a preliminarily set constant temperature for keeping transportation circumference of airtightly packaged body during the transportation period when the airtightly packaged body is transported by desired facilities for transportation, and a process 10 selling at a preliminarily set constant temperature for keeping selling circumference of airtightly packaged body when the airtightly packaged body is sold by desired facilities for sale.