The invention discloses an undressing-free automatic dejecta cleaner comprising a full-automatic processor and a toilet bowl. The toilet bowl is provided with a dejecta collecting area, a dejecta drain hole, a hot water input pipe and a hot air input pipe; the full-automatic processor comprises a shell body, a drainage bucket, a negative pressure device, a hot water device, a hot air device and acontrol device and is also provided with a packaging device which is connected with the drainage bucket and can seal and package dejecta and sewage; the toilet bowl is self-adaptive underwear made from a flexible material; the dejecta collecting area is arranged at the crotch of the self-adaptive underwear and made from a flexible waterproof material; and the full-automatic processor is also provided with a positive pressure device which can inflate the underwear and strut the dejecta collecting area to form an excretion space. The toilet bowl provided by the invention can be worn on a user for a long time, and the user does not need others' help for excretion, sanitation after excretion is simple to process, and the invention has the advantages of no troubles in undressing, simplicity inuse, convenience, comfort, and the like.