An improvement of a chemical bag warmer(body warmer) , which comprises a soft bag filled with a sodium acetate solution, and mounted therein with a triggering member;

the triggering member is a disc-shaped member, of which the center portion is a cross-shaped part extended to the edge thereof to divide the center portion into four sectors;

each sector has a plurality of fragmental concentrie circles to form into a rugged surface, the rugged surface can facilitate the triggering member to bend and vibrate so as to generate a better oscillation wave effect.