A hot rolled H-section steel comprising: a flange having a thickness of 100 mm to 150 mm; and a web, wherein the steel consists of, as a chemical composition, by mass%, C: 0.05% to 0.16%, Si: 0.01% to 0.50%, Mn: 0.80% to 2.00%, Ni: 0.05% to 0.50%, V: 0.01% to 0.20%. Al: 0.005% to 0.100%, Ti: 0.005% to 0.030%, N: 0.0010% to 0.0200%, O: 0.0001% to 0.0100%, Ca: 0.0003% to 0.0040%, Cr: 0% to 0.50%, Cu: 0% to 0.50%, Mo: 0% to 0.20%, Nb: 0% to 0.05%, P: limited to 0.03% or less, S: limited to 0.02% or less, and a balance consisting of Fe and impurities, a carbon equivalent Ceq obtained by the following expression is 0.35% to 0.50%, a number density of oxide particles having an equivalent circle diameter of 0.005 μm to 2.0 μm per unit area is 100 pieces/mm 2 to 5000 pieces/mm 2, the oxide particle includes Ca, Al, and O as a composition, an amount of Ca is 5% or more, an amount of Al is 5% or more, and a total amount of Ca and Al is 50% or more by mass ratio excluding O in the oxide particle, a bainite fraction in a metallographic structure of the flange is 80% or more at a strength evaluation position which is at a 1/6 position from a surface of the flange in a length direction and is at a 1/4 position from the surface of the flange in a thickness direction, and an average prior austenite grain size in the metallographic structure of the flange is 200 μm or less at a toughness evaluation position which is at a 1/2 position from the surface of the flange in the length direction and is at a 3/4 position from the surface of the flange in the thickness direction, and a yield strength or a 0.2% proof stress is 450 MPa or more, a tensile strength is 550 MPa or more, and a Charpy absorbed energy at 21 °C is 100 J or more at the strength evaluation position, Ceq = C + Mn / 6 + Cr + Mo + V / 5 + Ni + Cu / 15 here, C, Mn, Cr, Mo, V, Ni, and Cu in the expression represent an amount (mass%) of each element, and elements which are not added are indicated as 0. a flange having a thickness of 100 mm to 150 mm; and a web, wherein the steel consists of, as a chemical composition, by mass%, C: 0.05% to 0.16%, Si: 0.01% to 0.50%, Mn: 0.80% to 2.00%, Ni: 0.05% to 0.50%, V: 0.01% to 0.20%. Al: 0.005% to 0.100%, Ti: 0.005% to 0.030%, N: 0.0010% to 0.0200%, O: 0.0001% to 0.0100%, Ca: 0.0003% to 0.0040%, Cr: 0% to 0.50%, Cu: 0% to 0.50%, Mo: 0% to 0.20%, Nb: 0% to 0.05%, P: limited to 0.03% or less, S: limited to 0.02% or less, and a balance consisting of Fe and impurities, a carbon equivalent Ceq obtained by the following expression is 0.35% to 0.50%, a number density of oxide particles having an equivalent circle diameter of 0.005 μm to 2.0 μm per unit area is 100 pieces/mm 2 to 5000 pieces/mm 2, the oxide particle includes Ca, Al, and O as a composition, an amount of Ca is 5% or more, an amount of Al is 5% or more, and a total amount of Ca and Al is 50% or more by mass ratio excluding O in the oxide particle, a bainite fraction in a metallographic structure of the flange is 80% or more at a strength evaluation position which is at a 1/6 position from a surface of the flange in a length direction and is at a 1/4 position from the surface of the flange in a thickness direction, and an average prior austenite grain size in the metallographic structure of the flange is 200 μm or less at a toughness evaluation position which is at a 1/2 position from the surface of the flange in the length direction and is at a 3/4 position from the surface of the flange in the thickness direction, and a yield strength or a 0.2% proof stress is 450 MPa or more, a tensile strength is 550 MPa or more, and a Charpy absorbed energy at 21 °C is 100 J or more at the strength evaluation position, Ceq = C + Mn / 6 + Cr + Mo + V / 5 + Ni + Cu / 15 here, C, Mn, Cr, Mo, V, Ni, and Cu in the expression represent an amount (mass%) of each element, and elements which are not added are indicated as 0.