ELECTRIC RESISTANCE WELDED STEEL PIPE OR TUBE

Provided is an electric resistance welded steel pipe or tube that develops no quench cracks despite having carbon content of 0.40 % or more and has excellent fatigue strength. An electric resistance welded steel pipe or tube comprises: a chemical composition containing, in mass%, C: 0.40 % to 0.55 %, Si: 0.10 % to 1.0 %, Mn: 0.10 % to 2.0 %, P: 0.10 % or less, S: 0.010 % or less, Al: 0.010 % to 0.100 %, Cr: 0.05 % to 0.30 %, Ti: 0.010 % to 0.050 %, B: 0.0005 % to 0.0030 %, Ca: 0.0001 % to 0.0050 %, and N: 0.0005 % to 0.0050 %, with a balance consisting of Fe and inevitable impurities; and a ferrite decarburized layer at each of an outer surface and an inner surface, the ferrite decarburized layer having a depth of 20 µm to 50 µm from the surface.