An optical module of the present invention comprises first and second optical devices, a circuit board for outer connection, and a flexible substrate on which a part or all of an electronic circuit device group for each of the optical devices is mounted to electrically connect each of the optical devices to the circuit board for outer connection, wherein the flexible substrate has first and second substrate parts which are separated by a slit part that is elongated from an interspace between connection parts of the first and the second optical devices in a longitudinal direction of the flexible substrate. With this configuration, it is possible to provide an optical module capable of sufficiently and easily absorbing a positional deviation of a connection portion between an optical device and that of a print circuit board and capable of decreasing a cross talk between transmission and reception.