Terahertz wave-emission properties of a polysilicon solar cell excited by femtosecond laser pulses were visualized by laser terahertz emission microscopy (LTEM). The effects on the terahertz emissions of continuous-wave (cw) laser illumination of the solar cell at two wavelengths (808 and 365 nm) were examined under conditions of reverse and zero bias. The amplitude of the terahertz pulses in the presence of illumination was lower than that in its absence, and it decreased with increasing illumination power. The photovoltaic effect was smaller for cw laser illumination at the shorter wavelength. These phenomena can be explained in terms of screening of the electric field in the depletion layer of the p−n junction, as a result of the presence of photoexcited carriers. In addition, the LTEM images permitted the visualization of the crystalline grain structure of the solar cell and the dynamics of photocarriers, and they reflected the local electric field distribution in the cell. LTEM was therefore shown to be a promising technique for the evaluation and inspection of solar cells.