An encapsulation resin composition is used to hermetically seal a gap between a base member and a semiconductor chip bonded onto the base member. The encapsulation resin composition has a reaction start temperature of 160° C. or less. A melt viscosity of the encapsulation resin composition is 200 Pa·s or less at the reaction start temperature, 400 Pa·s or less at any temperature which is equal to or higher than a temperature lower by 40° C. than the reaction start temperature and which is equal to or lower than the reaction start temperature, and 1,000 Pa·s or less at a temperature lower by 50° C. than the reaction start temperature.