A polyarylene sulfide includes 0.01 to 5 mol %, per mol of arylene sulfide structural units, of a function group selected from the group consisting of an amino group, a carboxyl group, a hydroxyl group, an acid anhydride group, an isocyanate group, an epoxy group, a silanol group, and an alkoxysilane group having a dispersity represented by (weight average molecular weight)/(number average molecular weight) of 2.5 or less and a weight loss ratio at 100° C. to 330° C. of 0.2% by weight or less when the polyarylene sulfide is subjected to thermogravimetric analysis from 50° C. to 340° C. at a temperature ramp-up rate of 20° C./min under a non-oxidative atmosphere of normal pressure.