The present invention realizes an enhancement of a fabrication yield and a reduction of a size regarding an optical modulator or an optical device including polarization beam combining means. An optical modulator of the present invention (1) includes: first and second optical modulators (LN optical modulators (101) to (104)) that are formed on a substrate; a polarization beam rotating unit (107) that rotates at least one polarization beam of modulated light beams modulated by the first and second optical modulators; and a polarization beam combining element (110) that is disposed outside the substrate and that combines the polarization beams of the modulated light of which the polarization beams are rotated by the polarization beam rotating unit (107).