  We discuss topological objects, in particular the non-Abrikosov vortex and
the magnetic knot made of the twisted non-Abrikosov vortex, in two-gap
superconductor. We show that there are two types of non-Abrikosov vortex in
Ginzburg-Landau theory of two-gap superconductor, the D-type which has no
concentration of the condensate at the core and the N-type which has a
non-trivial profile of the condensate at the core, under a wide class of
realistic interaction potential. Furthermore, we show that we can construct a
stable magnetic knot by twisting the non-Abrikosov vortex and connecting two
periodic ends together, whose knot topology $\pi_3(S^2)$ is described by the
Chern-Simon index of the electromagnetic potential. We discuss how these
topological objects can be constructed in $\rm MgB_2$ or in liquid metallic
hydrogen.
