Thick-walled steel pipe for oil well and method of manufacturing same

Provided is a thick-walled steel pipe which is for an oil well and which has a thickness of 40 mm or more, an excellent SSC resistance, a high strength (827 MPa or more), and a small variation in strength in the thickness direction. Said thick-walled steel pipe for an oil well has a chemical composition containing, in mass%, 0.40-0.65% of C, 0.05-0.50% of Si, 0.10-1.0% of Mn, 0.020% or less of P, 0.0020% or less of S, 0.005-0.10% of sol. Al, 0.40-2.0% of Cr (excluding 0.40), 1.15-5.0% of Mo (excluding 1.15), 0.50% or less of Cu, 0.50% or less of Ni, 0.007% or less of N, and 0.005% or less of O. Furthermore, the number of carbides, which have an equivalent circle diameter of 100 nm or larger and contain 20 mass% or more of Mo, is two or less per 100 µm