We examine the direct bonding of (001) InP and (110) GaAs and demonstrate its application to device fabrication. Cross‐sectional observation shows that these wafers can be united without generating dislocation. (001) InP‐based 1.55‐μm wavelength lasers are fabricated on (110) GaAs. The light–current characteristics of the lasers are almost identical to those of lasers fabricated on (001) GaAs, while the turn‐on voltage is higher by about 0.4 V due to the large band discontinuity. The results show that the direct bonding technique is promising for allowing new concept ‘‘free‐orientation integration.’’