An optical module includes a first optical block, a second optical block, and a metal part. In a state that the metal part is assembled with the first optical block, the second optical block is sandwiched between the first optical block and the metal part. The metal part includes two spring pieces. The two spring pieces are along both lateral surfaces of the first optical block. Locking parts which are formed on both lateral surfaces of the first optical block are hooked on the two spring pieces. The second optical block is pressed against the first optical block in a direction, in which the metal part is assembled with the first optical block, by a spring force which is generated when the two spring pieces are hooked on the locking parts.