The present invention provides an adhesive composition for soft tissues, an adhesive composition for wound dressing or a wound dressing composition, not only having low toxicity, low harmfulness and high adhesive strength but also being excellent in workability during application and being capable of forming films of excellent properties. The compound of the present invention is comprised a monomer (A), polymer particles (B) having a specific weight-average molecular weight and a specific volume mean particle diameter, and a polymerization initiator composition (C) containing an organoboron compound is produced.