A three-piece can includes a can body obtained by forming a steel sheet such that a roundness of the can is 0.34 mm or less. The steel sheet contains: by mass %, C: 0.020% or more and 0.100% or less; Si: 0.10% or less; Mn: 0.10% or more and 0.80% or less; P: 0.001% or more and 0.100% or less; S: 0.001% or more and 0.020% or less; Al: 0.005% or more and 0.100% or less; and N: 0.0130% or more and 0.0200% or less. The balance is Fe and inevitable impurities. The steel sheet has a yield strength of 440 MPa or more and a total elongation of 12% or more.