A polyphenylene sulfide fiber has an amount of heat of crystallization measured by DSC is 10 J/g or more and the degree of shrinkage on dry heating of 150° C.×30 minutes is 20% or less. A method produces a densified wet-laid nonwoven fabric by subjecting paper produced in a papermaking process and containing 60 to 100% by mass of a polyphenylene sulfide fiber having an amount of heat of crystallization of 10 J/g or more and an amount of heat of crystallization of the wet-laid nonwoven fabric before heating-pressurizing treatments is 5 J/g or more to heating-pressurizing treatment at a temperature that is not lower than the glass transition temperature and not higher than the melting point of the polyphenylene sulfide fiber.