  We study the Josephson effect in spin-singlet superconductor/helical $p$-wave
superconductor junctions with a ferromagnetic barrier using the quasiclassical
Green function method. It is found that both $\sin{\phi}$-type and
$\cos{\phi}$-type current-phase relations always exist, irrespective of the gap
symmetries in superconductors. The indispensable condition for the
$\sin{\phi}$-type and $\cos{\phi}$-type current is that the magnetization must
have a component parallel to the crystallographic $a$ or $b$ axis, which is
distinct from the case of $p$-wave superconductor described by a
$\vect{d}$-vector with a uniform direction. The relation between the condition
and the symmetries of the gap functions is analysed. We investigate in detail
the symmetries and the sign reversal of the Josephson current when the
magnetization is rotated.
