To provide an optical module capable of improving the workability for a circuit substrate, in the rear of a shield case (22), a pressing portion (27) for holding an FOT (6) is formed to press a back surface of a package portion (9) of the FOT (6). In the rear of the shield case (22), a stress countermeasure portion (28) is formed to distribute or mitigate a stress occurring due to deformation and displacement of the pressing portion (27). The stress countermeasure portion (28) is formed between the pressing portion (27) and a substrate connection portion (16). The stress countermeasure portion (28) is formed in the vicinity of the pressing portion (27). In a small space between a base (or bend portion) of the pressing portion (27) and the stress countermeasure portion (28), the force in a twist direction acts due to the occurred stress. This force is distributed or absorbed according to presence and shape of the stress countermeasure portion (28).