The visualization of CO₂ emission in the lifestyle including food is thought recently to be essential for the sustainable society. In this paper, the estimation methods of the CO₂ emission for cooking in the household, especially for gas cooking such as “boil and steam”, “broil and stir-fry”, “deep fry(like tempra)” and “grill and oven” were developed based on the theoretical energy consumption to raise the food stuff temperature, which were calculated using their heat capacity and latent heat of the food stuffs and the energy efficiency of each gas cooker. The calculated values of the CO₂ emission using the estimation methods proposed in this paper corresponded well with the experimental values shown in the literatures. This estimation method is not only useful to show the consumers the CO₂ emission of the menu of household, but also might be useful to estimate the CO₂ emission of the menu in the restaurant.