Circuit module and optical device

A circuit module comprising:

• a first wiring board including a first main surface and a second main surface provided on an opposite side to the first main surface;
• and
• a second wiring board including a third main surface intersecting with a direction along the first main surface,
• wherein the first main surface and the second main surface of the first wiring board are soldered to the third main surface of the second wiring board,
• wherein the third main surface of the second wiring board includes an overlapping portion overlapping with the first wiring board in a first direction orthogonal to the third main surface, a first portion extending from the overlapping portion on one side in a second direction orthogonal to the first direction, and a second portion extending from the overlapping portion on another side in the second direction,
• wherein W2<W1 is satisfied where W1 represents a length of the first wiring board in a third direction orthogonal to the first direction and the second direction, and W2 represents a length of the second wiring board in the third direction,
• wherein L1<L2 is satisfied where L1 represents a length of the first portion in the second direction, and L2 represents a length of the second portion in the second direction, and
• wherein the circuit module further comprises a plurality of electronic parts mounted on the second portion.