We propose a novel approach to measure short electron bunch profiles at micrometer level. Low energy electrons generated during beam-gas ionization are simultaneously modulated by the transverse electric field of a circularly-polarized laser, and then they are collected at a down-stream screen where the angular modulation is converted to a circular shape. The longitudinal bunch profile is simply represented by the angular distribution of the electrons on the screen. We only need to know the laser wavelength for calibration and there is no phase synchronization problem. Meanwhile the required laser power is also relatively low in this setup. Some simulations examples and experimental consideration of this method are discussed. Show Partial Abstract