- We study small-scale fluctuations of number density of inertial particles in turbulent flow. Anomalous scaling for second-order correlation function of number density of inertial particles is found, and the mechanism for the anomalous scaling is associated with inertia of particles which results in a divergent velocity field. The anomalous scaling appears already in the second moment when the degree of compressibility σ>1/27 (where σ is the ratio of energies in compressible and incompressible components of particle velocities). It is also demonstrated that inertia of particles in a homogeneous isotropic turbulent flow causes a self-exictation (exponential growth) of fluctuations of particle concentration. The growth rates of the higher moments of particle concentration is higher than those of the lower moments, i.e., the particle spatial distribution is intermittent.