A resin composition is provided which has high transparency, light guiding properties and luminescent properties and can guide light therethrough with little change in chromaticity. A shaped article such as an optical element including the resin composition is also provided. The resin composition includes an acrylic block copolymer (A) and a light diffusing agent (B), wherein the acrylic block copolymer (A) has at least one structure in which polymer blocks (a1) based on methacrylic acid ester units are bonded to both ends of a polymer block (a2) based on acrylic acid ester units, and has a weight average molecular weight of 10,000 to 150,000 and a tensile elastic modulus of 1 to 1,500 MPa, the light diffusing agent (B) is rutile titanium oxide having an average particle size of 0.5 to 2.0 μm, and the content of the light diffusing agent (B) is 0.5 to 10 ppm (on mass basis) based on the acrylic block copolymer (A).