A thermoplastic resin composition comprising an olefin-based polymer (a) and a hydrogenated block copolymer (b), wherein: with respect to the olefin-based polymer (a), an amount of heat of crystal fusion (ΔH) measured at a heating rate of 10°C/min in differential scanning calorimetry is less than 80 J/g; the hydrogenated block copolymer (b) is a hydrogenated product of a block copolymer composed of a polymer block consisting mainly of a structural unit derived from an aromatic vinyl compound and a polymer block consisting mainly of a structural unit derived from a conjugated diene compound; the content of the polymer block in the hydrogenated block copolymer (b) is from 5 to 60% by mass; a proportion of a vinyl bond amount of the polymer block is from 50 to 95 mol%; the content of the hydrogenated block copolymer (b) in the thermoplastic resin composition is from 1 to 30 parts by mass relative to 100 parts by mass of the total amount of the olefin-based polymer (a) and the hydrogenated block copolymer (b); and the olefin-based polymer (a) and the polymer block of the hydrogenated block copolymer (b) are made miscible with each other on a molecular level, wherein the olefin-based polymer (a) is at least one olefin-based polymer selected from the group consisting of a non-crystalline or low-crystalline poly-α-olefin and a polyolefin elastomer, and wherein in the temperature dispersion measurement of dynamic viscoelasticity of the thermoplastic resin composition, the number of maximum peaks of a loss modulus (G") appearing in a temperature range of -70 to 0°C is one, with the measuring conditions for the dynamic viscoelasticity being as follows: parallel plate: diameter, 8 mm; vibration mode: torsional vibration; strain amount: 0.1%; frequency: 1 Hz; measuring temperature: -70 to 0°C; and temperature rise rate: 3°C/min. with respect to the olefin-based polymer (a), an amount of heat of crystal fusion (ΔH) measured at a heating rate of 10°C/min in differential scanning calorimetry is less than 80 J/g; the hydrogenated block copolymer (b) is a hydrogenated product of a block copolymer composed of a polymer block consisting mainly of a structural unit derived from an aromatic vinyl compound and a polymer block consisting mainly of a structural unit derived from a conjugated diene compound; the content of the polymer block in the hydrogenated block copolymer (b) is from 5 to 60% by mass; a proportion of a vinyl bond amount of the polymer block is from 50 to 95 mol%; the content of the hydrogenated block copolymer (b) in the thermoplastic resin composition is from 1 to 30 parts by mass relative to 100 parts by mass of the total amount of the olefin-based polymer (a) and the hydrogenated block copolymer (b); and the olefin-based polymer (a) and the polymer block of the hydrogenated block copolymer (b) are made miscible with each other on a molecular level, wherein the olefin-based polymer (a) is at least one olefin-based polymer selected from the group consisting of a non-crystalline or low-crystalline poly-α-olefin and a polyolefin elastomer, and wherein in the temperature dispersion measurement of dynamic viscoelasticity of the thermoplastic resin composition, the number of maximum peaks of a loss modulus (G") appearing in a temperature range of -70 to 0°C is one, with the measuring conditions for the dynamic viscoelasticity being as follows: parallel plate: diameter, 8 mm; vibration mode: torsional vibration; strain amount: 0.1%; frequency: 1 Hz; measuring temperature: -70 to 0°C; and temperature rise rate: 3°C/min. parallel plate: diameter, 8 mm; vibration mode: torsional vibration; strain amount: 0.1%; frequency: 1 Hz; measuring temperature: -70 to 0°C; and temperature rise rate: 3°C/min.