The shortest possible lasing wavelength and the lowest threshold current density of the GaInAsP visible injection laser diodes grown on (100) GaAs substrate by the liquid phase epitaxy using a two‐phase solution growth technique are discussed. The lasing wavelength and threshold current density at room temperature under pulsed conditions are 705 nm and 9.4 kA/cm2, respectively. Light output power of 5–6 mW from one facet and maximum differential quantum efficiency of 38% are realized under the condition of fundamental lateral and transverse mode operation.