A heat insulating vessel including an inner tank having a vertical axis to accommodate low temperature liquefied gas, an outer tank externally around the inner, and a low temperature liquefied gas pump disposed inside the inner tank. The outer tank having an upper part and an outer tank body. A lid structure having a heat-insulated structure detachably fitted into an upper part of the inner. The heat insulating vessel includes a first fastener to fasten with bolts, a first flange to upper ends of the inner and outer tanks upper part to a second flange to an outer circumferential part of the lid structure, and a second fastener to fasten with bolts, a third flange to an upper end of the outer tank body to a fourth flange to a lower end of the outer tank upper part. A vacuum insulating layer is formed between the inner and outer tanks.