  A possible solution to the strong CP problem is presented without using an
axion. The model is based on the framework of the supersymmetric vectorlike
theory with the spontaneous breakdown of the P-C-T-invariance. It is shown that
the characteristic structure of the Yukawa coupling matrices that results from
the spontaneous P-C-T-breaking plays the essential role in naturally realizing
$\theta=0$ at the tree level. It is argued that $\theta=0$ will not be affected
by the radiative corrections.
