Hydraulic compositions comprising a setting accelerator, a water-soluble cellulose ether having a degree of alkyl substitution of 1.6 to 2.5 which is a water-soluble alkyl cellulose or a water-soluble hydroxyalkyl alkyl cellulose, and water are useful as self-leveling compositions having an excellent self-leveling capability, a minimal change with time of fluidity, and a short setting time, or as cement mortar compositions having a long open time and a short setting time.