Ca3Ta(Ga1-xAlx)(3)Si2O14 [CTGAS] material is a piezoelectric material belonging to the Langasite-type group (space group: P321). and the CTGAS single crystals (x= 0, 0.25, 0.50, 0.75) with a diameter of 1 in. were grown by a Czochralski [Cz] method using an Ir crucible under Ar+ 2% O-2. The CTGAS single crystals without any cracks could be grown using a CTGAS seed crystal in the x range of 0 <= x <= 0.75. Cell parameters, a and c, decrease while the a/c ratio increased with the Al concentration. Piezoelectric constant d11 and electromechanical coupling factor k12 for the X-cut specimens of the CTGAS single crystals were increased by the Al substitution.