  We demonstrate the possibility of a good description of the processes $\phi
(1020)\to \gamma\pi\pi$ and $\phi (1020)\to \gamma f_0(980)$ within the
framework of non-relativistic quark model assuming $f_0(980)$ to be dominantly
quark--antiquark system. Different mechanisms of the radiative decay, that is,
the emission of photon by the constituent quark (additive quark model) and
charge-exchange current, are considered. We also discuss the status of the
threshold theorem applied to the studied reactions, namely, the behaviour of
the decay amplitude at $M_{\pi\pi} \to m_\phi$ and $m_{f_0}\to m_\phi$. In
conclusion the arguments favouring the $q\bar q$ origin of $f_0(980)$ are
listed.
