PURPOSE: To convert meat into soft and tasty meat by subjecting the meat to ultrasonic treatment under specific conditions.

CONSTITUTION: Meat is subjected to ultrasonic treatment with ultrasonic waves at ≤100kHz frequency. The meat is preferably sandwiched between a processing tool 6 for outputting the ultrasonic waves to the meat 5 and an ultrasonic reflecting table 7 to perform the ultrasonic treatment.