To provide a dressing gown to be worn on a pajama, capable of thermally insulating the body during the wearer's daily activities such as going to bed or those in the night-time or in the early morning.

This dressing gown is made up of the front sections, back section and sleeves, each consisting of a hygroscopic material, and designed that the length around the chest is 1.3-2 times that of the circumference of the wearer's chest; and the dimension of the joint bearing a fastener 5 between the left and right front sections is so designed as to correspond to such a length over the knee as to allow the wearer's legs to spread apart from the upper part of the front section.