Polyorganosilsesquioxane, hard coat film, adhesive sheet, and laminate

The purpose of the present invention is to provide a polyorganosilsesquioxane which can be cured into a cured article having high surface hardness and heat resistance and also having excellent flexibility and processability. The present invention relates to a polyorganosilsesquioxane characterized by having a constituent unit represented by formula (1), wherein the molar ratio of the constituent unit represented by formula (I) to a constituent unit represented by formula (II) [i/e., (constituent unit represented by formula (I))/(constituent unit represented by formula (II))] is 5 or more, the ratio of the total amount of a constituent unit represented by formula (1) and a constituent unit represented by formula (4) to the total amount of all of siloxane constituent units (100% by mole) is 55 to 100% by mole, the number average molecular weight of the polyorganosilsesquioxane is 1000 to 3000, and the degree of distribution of the molecular weight (i.e., (weight average molecular weight)/(number average molecul