A heat insulating member includes a wall member. The wall member includes a high-density portion provided at one end edge in a direction orthogonal to a thickness direction of the wall member and having density of above 0.45 g/cm3 and a low-density portion provided midway in the direction orthogonal to the thickness direction, having heat-insulating properties, and having density of 0.45 g/cm3 or less. The high-density portion is provided over the entire one end edge and the thickness of the high-density portion is thinner than that of the low-density portion.