Hydrogenated amorphous carbon(a-C:H) films were fabricated by the low-frequency (60Hz) glow discharge of the mixture of methane and hydrogen, and their electrical properties were investigated. We observed that a-C:H films show the persistent photoconductivity(PPC) by illumination of heat-filtered while light for a few seconds. The PPC was about 10 times larger than the annealed dark conductivity. The samples clearly showed metastable characteristics. With increasing illumination times from 1 to 100 min, the annealing activation energy of the PPC was about 0.39eV. The annealing temperature at which the PPC disappeared increasing from $100^{circ}C$ to $130^{circ}C$. Illumination longer than 80 min leads to the formation of ${pi}$ defects and to the decrease of PPC. From these results, we tentatively propose that the states in the ${pi}$ band act as deep trap centers generating the metastabilities.