The invention provides a bread hardening preventing agent, a bread hardening-preventing method, a bread production method, a premix flour for bread for the purpose of obtaining a bread whose hardening is prevented, thereby providing a bread whose hardening is satisfactorily prevented. A bread hardening preventing agent whose active ingredient is a rice flour whose damaged starch content is 15% by mass or more; a bread hardening preventing agent whose active ingredient is a rice flour whose damaged starch content is more than 30% by mass; a bread hardening-preventing method for producing a bread which incorporates a rice flour whose damaged starch content is 15% by mass or more; a bread production method which incorporates a rice flour whose damaged starch content is 15% by mass or more; a premix flour for bread containing 0.01 to 15 parts by mass of a rice flour whose damaged starch content is 15% by mass or more based on 100 parts by mass of a wheat flour; a bread in which a rice flour whose damaged starch c
