A hot-rolled steel sheet having the following chemical composition and metallographic structure: chemical composition: it consists of, in mass percent, C: 0.05 - 0.20%, Si: 0.02 - 3.0%, Mn: 0.5 - 3.0%, Cr: 0.05 - 1.0%, sol. Al: 0.01 - 1.0%, one or more elements selected from the group consisting of Ti, Nb, Mo, V, and W: a total of 0.002 - 0.03%, optionally one or more of Ca, Mg, and REM in a total amount of at most 0.0050%, and a remainder of Fe and impurities, the impurities including P: at most 0.5% and S: at most 0.05%; metallographic structure: a region of from 100 μm to 200 μm in the sheet thickness direction from the surface of the steel sheet consists of ferrite and a remaining structure, the remaining structure being bainite, martensite, retained austenite or granular cementite, preferably bainite, tempered martensite, bainite and tempered martensite, or granular cementite, the average grain diameter of ferrite is at most 3.0 μm in the region of from 100 μm to 200 μm in the sheet thickness direction from the surface of the steel sheet, the average grain diameter of ferrite being obtained by the intercept method based on an image taken by a scanning electron microscope in a cross section in the lengthwise direction of rolling which has been mirror polished and etched with a nital solution, the region of from 100 μm to 200 μm in the sheet thickness direction from the surface of the steel sheet contains 30 - 80% by area of ferrite, and the average spacing in the sheet thickness direction and the average spacing in the rolling direction of the remaining structure in the region of from 100 μm to 200 μm in the sheet thickness direction from the surface of the steel sheet is at most 3.0 μm, the average spacing being determined by drawing a line with a length of 80 μm, measuring the spacing between facing phases of the remaining structure, repeating these procedures at 5 arbitrary locations, and calculating the average of the measured values. chemical composition: it consists of, in mass percent, C: 0.05 - 0.20%, Si: 0.02 - 3.0%, Mn: 0.5 - 3.0%, Cr: 0.05 - 1.0%, sol. Al: 0.01 - 1.0%, one or more elements selected from the group consisting of Ti, Nb, Mo, V, and W: a total of 0.002 - 0.03%, optionally one or more of Ca, Mg, and REM in a total amount of at most 0.0050%, and a remainder of Fe and impurities, the impurities including P: at most 0.5% and S: at most 0.05%; metallographic structure: a region of from 100 μm to 200 μm in the sheet thickness direction from the surface of the steel sheet consists of ferrite and a remaining structure, the remaining structure being bainite, martensite, retained austenite or granular cementite, preferably bainite, tempered martensite, bainite and tempered martensite, or granular cementite, the average grain diameter of ferrite is at most 3.0 μm in the region of from 100 μm to 200 μm in the sheet thickness direction from the surface of the steel sheet, the average grain diameter of ferrite being obtained by the intercept method based on an image taken by a scanning electron microscope in a cross section in the lengthwise direction of rolling which has been mirror polished and etched with a nital solution, the region of from 100 μm to 200 μm in the sheet thickness direction from the surface of the steel sheet contains 30 - 80% by area of ferrite, and the average spacing in the sheet thickness direction and the average spacing in the rolling direction of the remaining structure in the region of from 100 μm to 200 μm in the sheet thickness direction from the surface of the steel sheet is at most 3.0 μm, the average spacing being determined by drawing a line with a length of 80 μm, measuring the spacing between facing phases of the remaining structure, repeating these procedures at 5 arbitrary locations, and calculating the average of the measured values. <EOS>