[Problem] To provide a curable organopolysiloxane composition which forms a pressure sensitive adhesive layer having a relatively low storage elastic modulus (G') at low temperatures, excellent curability, and sufficient adhesion for practical use, along with the applications thereof.[Resolution Means] A pressure sensitive adhesive layer-forming organopolysiloxane composition, including: (A) a chain organopolysiloxane having alkenyl groups; (B) an organopolysiloxane resin which has a content of 9 moles or less of hydroxyl groups and the like is a mixture of (b1) an organopolysiloxane resin having an weight average molecular weight (Mw) of 4500 or more and (b2) an organopolysiloxane resin having a weight average molecular weight (Mw) of less than 4500; (C) an organohydrogenpolysiloxane; and (D) a hydrosilylation reaction catalyst, wherein the mass ratio of component (B) to component (A) is within a range of 0.9 to 2.0, and the shear storage elastic modulus G' at -20°C of a pressure sensitive adhesive layer obtained by curing the composition is within a range of 0.01 to 0.75 MPa.