[Object] Provided are a sheet-like molded article having excellent surface smoothness, moldability, flexibility, and a high transmittance of short-wavelength light, and a thermoplastic polymer composition used to produce the sheet-like molded article.[Solution] A thermoplastic polymer composition containing an acrylic block copolymer (A) and an acrylic resin (B), in which the acrylic block copolymer (A) has, in its molecule, at least one structure where polymer blocks (a2) mainly composed of a methacrylic ester unit are bonded to both ends of a polymer block (a1) mainly composed of an acrylic ester unit, the acrylic block copolymer (A) having a specific weight-average molecular weight range, the acrylic block copolymer (A) contains an acrylic block copolymer (A1) having a polymer block (a2) content of 40% by mass or more and not less than 80% by mass and contains an acrylic block copolymer (A2) having a polymer block (a2) content of 10% by mass or more and less than 40% by mass, the acrylic resin (B) is mainly composed of a methacrylic ester unit, and the mass ratio [(A)/(B)] is in the range of 97/3 to 10/90.