The remnant of a supernova explosion is widely believed to be the acceleration site of high-energy cosmic-ray particles. The acceleration timescale is, however, typically very long. Here, we report the detection of a variable gamma-ray source with the Fermi Large Area Telescope, which is positionally and temporally consistent with a peculiar supernova, iPTF14hls. A quasi-stellar object SDSS J092054.04+504251.5, which is probably a blazar candidate according to the infrared data, is found in the error circle of the gamma-ray source. More data about the gamma-ray source and SDSS J092054.04+504251.5 are needed to confirm their association. On the other hand, if the association between the gamma-ray source and the supernova is confirmed, this would be the first time detecting high-energy gamma-ray emission from a supernova, suggesting very fast particle acceleration by supernova explosions.