An optical module 1 according to an embodiment includes a plurality of laser diodes (LDs) 21 to 23, a multiplexing optical system 30 combining a plurality of laser beams from the respective plurality of LDs, and a package 10 accommodating the plurality of LDs and the multiplexing optical system. The package includes a support mounted with the plurality of LDs and the multiplexing optical system, and a cap having a transmissive window that allows a resultant light beam to pass through. At least one of the LDs has an oscillation wavelength of nor more than 550 nm. The package has an internal moisture content of not more than 3000 ppm. The multiplexing optical system is fixed to the support by a resin curing adhesive.