A sintered body manufacturing method includes: a preparation step of preparing a raw material powder containing an iron-based metal powder; a molding step of subjecting the raw material powder to uniaxial pressing using a die to produce a green compact having an overall average relative density of 93% or more; a machining step of machining the green compact to produce a machined compact; and a sintering step of sintering the machined compact to obtain a sintered body.