The photoelectric steady-state currents J_L in liquid Ar, liquid CH₄ and liquid N₂ were measured, changing the level of injection current. The current level was varied over a wide range using ultra violet light from a deuterium lamp. In liquid Ar and liquid CH₄, when the current in vacuum J_v (which is defined as an injection current) was less than 0.1 nA cm^-2. J_L was proportional to the external field E₀ at low fields, while at high fields J_L was proportional to E₀^1/2. However, by increasing J_V at low fields a space-charge-limited J_L was observed, with the linear relation between J_L and E₀^1/2 being unchanged at high fields. On the basis of measured curves of J_L against E₀, the distributions of space charge, field strength, and currents of electron and negative ion components within the gap were simulated. The space charge was presumed to appear due to accumulation of negative ions produced through attachment of electrons to oxygen impurities which might be included originally in gas samples. In liquid N₂, J_L was proportional to E₀^1.8-2, although it increased proportionally with J_V.