To obtain a thawing device simplified in the structure, little in drips, capable of uniformly thawing and improved in safety by forming wall surfaces composing a thawing chamber so as not to be parallel to each other and disposing a sound wave-generating means for projecting sound waves under the atmospheric pressure.

This thawing device is provided with a thawing chamber 6 for receiving a material to be thawed therein and with a sound wave-generating means comprising a speaker 7 and a transmitter-having amplifier 8 for projecting sound waves into the thawing chamber 6. The walls of the thawing chamber 6, such as a lid 9, a bottom surface 10 and sidewalls 11, are formed so as not to be parallel to each other, and the sound wave-generating means projects the sound waves under the atmospheric pressure. The wall surfaces are preferably formed in uneven surface states, and the sound waves to be projected are preferably white noises approximately uniformly containing the frequencies of a prescribed range.