PURPOSE: To obtain a substrate without crack and chipping of the cut part, by sticking the wafer reverse face to the adhesive tape, where a paste layer thicker than the height of ruggedness generated on the wafer reverse face is provided, and by cuting the piezoelectric material wafer to obtain the piezoelectric substrate.

CONSTITUTION: When rotary blade 34 is used to cut piezoelectric material wafer 30 consisting of LiTaO3 and so on, where element pattern 31 is formed on the surface, to obtain individual piezoelectric subsrates, adhesive tape 32 having a paste layer thicker than the height of ruggedness of average ruggedness 10∼15μm generated on the reverse face of wafer 30 normally is stuck to the reverse face of wafer 30. After that, the exposed side of tape 32 is sucked and fixed by chuck tape 33 where many vacuum holes are provided, and under this state, rotary blade 34 is pressed to the upper face of wafer 30 to divide wafer 30 into individual substrates. Thus, wafer 30 cannot be moved at a division time, and cracks can be prevented from being generated.