To provide a method for producing N-vinyl carboxylic acid amide polymer by an aqueous solution polymerization method, which is an efficient production method wherein gelatinous polymer excellent in handleability is produced and polymerization time is shortened.

The method for producing N-vinyl carboxylic acid amide polymer comprises polymerizing a monomer containing N-vinyl carboxylic acid amide in the presence of 7 mass% or more and a saturation solubility or less at polymerization initiation temperature of an inorganic salt based on water in an aqueous homogeneous solution containing the monomer, for aqueous polymerization of the monomer containing N-vinyl carboxylic acid amide.