  Energy levels of the double $\Lambda$ hypernucleus, $^{11}_{\Lambda
\Lambda}$Be are calculated within the framework of an $\alpha \alpha n \Lambda
\Lambda$ five-body model. Interactions between constituent particles are
determined so as to reproduce reasonably the observed low-energy properties of
the $\alpha \alpha$, $\alpha \alpha n$ nuclei and the existing data for
$\Lambda$-binding energies of the $\alpha \Lambda$, $\alpha \alpha \Lambda$,
$\alpha n \Lambda$ and $\alpha \alpha n \Lambda$ systems. An effective $\Lambda
\Lambda$ interaction is constructed so as to reproduce, within the $\alpha
\Lambda \Lambda$ three-body model, the $B_{\Lambda \Lambda}$ of $^6_{\Lambda
\Lambda}$He, which was extracted from the emulsion experiment, the NAGARA
event. With no adjustable parameters for the $\alpha \alpha n \Lambda \Lambda$
system, $B_{\Lambda \Lambda}$ of the ground and bound excited states of
$^{11}_{\Lambda \Lambda}$Be are calculated with the Gaussian Expansion Method.
The Hida event, recently observed at KEK-E373 experiment, is interpreted as an
observation of the ground state of the $^{11}_{\Lambda \Lambda}$Be.
