Ester production method and ester production device

Provided is a production device including: a first reactor to form a second gas containing an ester and nitric oxide from a first gas containing carbon monoxide, a nitrite, and nitric oxide; an absorption column to separate the second gas and an absorbing solution into a condensate containing the ester and a noncondensable gas; a second reactor to introduce an alcohol, the noncondensable gas, and oxygen gas thereinto to form a third gas containing nitric oxide and a nitrite; a third reactor to form a fourth gas containing a nitrite from the noncondensable gas and a bottom liquid from the second reactor and to feed the fourth gas to the second reactor; a first measurement unit to measure the concentration of a nitrite in the first gas; and a first flow rate-adjusting unit to adjust the amount of the noncondensable gas to the third reactor based on the concentration.