  Quantum correlations in observables of multiple systems not only are of
fundamental interest, but also play a key role in quantum information
processing. As a signature of these correlations, the violation of Bell
inequalities has not been demonstrated with multipartite hybrid entanglement
involving both continuous and discrete variables. Here we create a five-partite
entangled state with three superconducting transmon qubits and two photonic
qubits, each encoded in the mesoscopic field of a microwave cavity. We reveal
the quantum correlations among these distinct elements by joint Wigner
tomography of the two cavity fields conditional on the detection of the qubits
and by test of a five-partite Bell inequality. The measured Bell signal is
$8.381\pm0.038$, surpassing the bound of 8 for a four-partite entanglement
imposed by quantum correlations by 10 standard deviations, demonstrating the
genuine five-partite entanglement in a hybrid quantum system.
