A method of producing a valve guide made of an iron-based sintered alloy, the method comprising the steps of: molding raw material powder including diffusion-alloyed powder including core iron powder and Cu bonded to the core iron powder through diffusion to obtain a molded body; and sintering the molded body at a sintering temperature that falls within a range of from 1,102°C to 1,152°C, to thereby produce a valve guide made of an iron-based sintered alloy, wherein a sintering time period in the sintering step falls within a range of from 10 minutes to 2 hours, the raw material powder having a content of a Cu component falling within a range of from 14 mass% to 40 mass%, a ratio of a Cu component derived from the diffusion-alloyed powder including core iron powder and Cu bonded to the core iron powder through diffusion with respect to the Cu component contained in the raw material powder being 45% or more, wherein the iron-based sintered alloy is free of Ni, and wherein the iron-based sintered alloy has a structure including pores and a Cu phase, wherein a pore area ratio of the pores is 3% or more and 15% or less, and wherein a Cu area ratio of the Cu phase is from 11% to 36%, wherein the pore area ratio and the Cu area ratio are measured by photographing a cross section of the valve guide with a laser microscope at a magnification of 20 times, the cross section being obtained by cutting the valve guide in a direction perpendicular to an axial direction, and binarizing the obtained image data to determine the ratio of the area of the pores and the area of the Cu phase with respect to the total area of the observation field, thereby determining the pore area ratio and the Cu area ratio. molding raw material powder including diffusion-alloyed powder including core iron powder and Cu bonded to the core iron powder through diffusion to obtain a molded body; and sintering the molded body at a sintering temperature that falls within a range of from 1,102°C to 1,152°C, to thereby produce a valve guide made of an iron-based sintered alloy, wherein a sintering time period in the sintering step falls within a range of from 10 minutes to 2 hours, the raw material powder having a content of a Cu component falling within a range of from 14 mass% to 40 mass%, a ratio of a Cu component derived from the diffusion-alloyed powder including core iron powder and Cu bonded to the core iron powder through diffusion with respect to the Cu component contained in the raw material powder being 45% or more, the raw material powder having a content of a Cu component falling within a range of from 14 mass% to 40 mass%, a ratio of a Cu component derived from the diffusion-alloyed powder including core iron powder and Cu bonded to the core iron powder through diffusion with respect to the Cu component contained in the raw material powder being 45% or more, wherein the iron-based sintered alloy is free of Ni, and wherein the iron-based sintered alloy has a structure including pores and a Cu phase, wherein a pore area ratio of the pores is 3% or more and 15% or less, and wherein a Cu area ratio of the Cu phase is from 11% to 36%, wherein the pore area ratio and the Cu area ratio are measured by photographing a cross section of the valve guide with a laser microscope at a magnification of 20 times, the cross section being obtained by cutting the valve guide in a direction perpendicular to an axial direction, and binarizing the obtained image data to determine the ratio of the area of the pores and the area of the Cu phase with respect to the total area of the observation field, thereby determining the pore area ratio and the Cu area ratio. <EOS>