Stripe‐ and ridge‐geometry in InGaN multi‐quantum‐well (MQW)‐structure laser diodes (LDs) were fabricated on sapphire substrates with (112¯0) orientation (A face). The ridge‐geometry InGaN MQW LDs showed strong stimulated emission at a wavelength of 411.3 nm under a pulsed current injection of 199 mA at room temperature. The differential quantum efficiency per facet and the threshold current of ridge‐geometry LDs were 30% and 180 mA, respectively. The laser threshold current density was 3 kA/cm2. These values were greatly improved in comparison to those of stripe‐geometry LDs. The characteristic temperature of the threshold current was around 185 K. ©1996 American Institute of Physics.