The present invention relates to a product for daily life, and more particularly, to a container for covering a PET bottle that is capable of providing thermal insulation effects for the beverage contained in the PET bottle. The container for covering a PET bottle includes: a cap adapted to cover the upper portion of the PET bottle; and a body adapted to be coupled with the cap and to cover the lower portion of the PET bottle. As the container for covering a PET bottle forms a double bottle structure together with the PET bottle therein, the container can prevent a neighboring object or a user's had from coming into contact with condensed water generated due to dew condensation or the outer surface of the PET bottle which is carried, thereby keeping the neighboring object or user's hand from getting wet or keeping dirt from becoming attached to the PET bottle. Also, as the container has thermal insulation effects, warm or cold beverages remain drinkable over an extended time period. In addition, the container can be generally used for most of plastic beverage bottles on the market.