A method for producing acetic acid, comprising: a carbonylation reaction step of reacting methanol with carbon monoxide in the presence of a catalyst system comprising a metal catalyst and methyl iodide, acetic acid, methyl acetate, and water in a reaction vessel to produce acetic acid; an evaporation step of separating the reaction mixture obtained in the carbonylation reaction step into a vapor stream and a residual liquid stream in an evaporator; a residual liquid stream recycle step of bringing the residual liquid stream back to the reaction vessel; and a distillation step of distilling the vapor stream to purify acetic acid, wherein the evaporator has a body part connected with a reaction mixture feed line, a top part connected with a vapor stream discharge line, and a bottom part connected with a residual liquid stream recycle line, the body part having an upper cylindrical portion having a large diameter, a lower cylindrical portion having a small diameter, and an inverted truncated conical cylindrical connection portion which joins the upper cylindrical portion and the lower cylindrical portion, and has at least one of the following catalyst precipitation and accumulation prevention structures (a) and (b): (a) a structure where an inclination angle θ of inside wall surface of the inverted truncated conical cylindrical connection portion of the evaporator is 5° to 85°; and (b) a structure where a vortex breaker comprising a plate-like vortex breaker main body and a leg which horizontally supports the vortex breaker main body is disposed such that the vortex breaker main body covers right above the connection portion of the evaporator bottom part to the residual liquid stream recycle line, and the structure is designed such that a linear velocity r of the residual liquid stream passing through a gap between the circumferential end of the vortex breaker main body and the inside bottom surface of the evaporator bottom part is larger than 10 m/h. a carbonylation reaction step of reacting methanol with carbon monoxide in the presence of a catalyst system comprising a metal catalyst and methyl iodide, acetic acid, methyl acetate, and water in a reaction vessel to produce acetic acid; an evaporation step of separating the reaction mixture obtained in the carbonylation reaction step into a vapor stream and a residual liquid stream in an evaporator; a residual liquid stream recycle step of bringing the residual liquid stream back to the reaction vessel; and a distillation step of distilling the vapor stream to purify acetic acid, wherein the evaporator has a body part connected with a reaction mixture feed line, a top part connected with a vapor stream discharge line, and a bottom part connected with a residual liquid stream recycle line, the body part having an upper cylindrical portion having a large diameter, a lower cylindrical portion having a small diameter, and an inverted truncated conical cylindrical connection portion which joins the upper cylindrical portion and the lower cylindrical portion, and has at least one of the following catalyst precipitation and accumulation prevention structures (a) and (b): (a) a structure where an inclination angle θ of inside wall surface of the inverted truncated conical cylindrical connection portion of the evaporator is 5° to 85°; and (b) a structure where a vortex breaker comprising a plate-like vortex breaker main body and a leg which horizontally supports the vortex breaker main body is disposed such that the vortex breaker main body covers right above the connection portion of the evaporator bottom part to the residual liquid stream recycle line, and the structure is designed such that a linear velocity r of the residual liquid stream passing through a gap between the circumferential end of the vortex breaker main body and the inside bottom surface of the evaporator bottom part is larger than 10 m/h. (a) a structure where an inclination angle θ of inside wall surface of the inverted truncated conical cylindrical connection portion of the evaporator is 5° to 85°; and (b) a structure where a vortex breaker comprising a plate-like vortex breaker main body and a leg which horizontally supports the vortex breaker main body is disposed such that the vortex breaker main body covers right above the connection portion of the evaporator bottom part to the residual liquid stream recycle line, and the structure is designed such that a linear velocity r of the residual liquid stream passing through a gap between the circumferential end of the vortex breaker main body and the inside bottom surface of the evaporator bottom part is larger than 10 m/h.