The present invention provides a process for producing acrolein, which exhibits a prolonged catalyst life, low energy consumption, and excellent efficiency, and which is earth-conscious, and a glycerin-containing composition which can preferably be used even in this process. The process for producing acrolein is one which includes bringing a raw material gas containing glycerin gas into contact with a solid acid catalyst in a reactor, and the partial pressure of the glycerin gas in the raw material gas is set to be from 0.01 to 30 kPa. The glycerin-containing composition is for use in a process for producing acrolein using a solid catalyst and includes a fatty acid and/or a fatty acid ester, and a total mass of the fatty acid and the fatty acid ester is from 0.001% to 5% by mass, relative to the glycerin.