  We study the heavy quark spin (HQS) multiplet structure of P-wave
$Q\bar{Q}qqq$-type pentaquarks treated as molecules of a heavy meson and a
heavy baryon. We define the light-cloud spin (LCS) basis decomposing the
meson-baryon spin wavefunction into the LCS and HQS parts. Introducing the LCS
basis, we find HQS multiplets classified by the LCS; five HQS singlets, two HQS
doublets, and three HQS triplets. We construct the one-pion exchange potential
respecting the heavy quark spin and chiral symmetries to demonstrate which HQS
multiplets are realized as a bound state. By solving the coupled channel
Schr\"odinger equations, we study the heavy meson-baryon systems with $I=1/2$
and $J^P=(1/2^+, 3/2^+, 5/2^+, 7/2^+)$. The bound states which have same LCS
structure are degenerate at the heavy quark limit, and the degeneracy is
resolved for finite mass. This HQS multiplet structure will be measured in the
future experiments.
