An optical transmitting and receiving module holder that can quickly, easily, and accurately adjust the relative positions of an optical transmitting module holder section and an optical receiving module holder section is provided. An optical transmitting and receiving module holder includes a first optical module holder section and a second optical module holder section. A lens is integrally formed between an optical fiber attaching section and a photoelectric conversion element housing section in the first optical module holder section. A lens is integrally formed between an optical fiber attaching section and a photoelectric conversion element housing section in the second optical module holder section. Any of a plurality of protruding sections formed on side surfaces of the photoelectric conversion element housing section of the second optical module holder section is engaged with a groove section formed on a side surface of the photoelectric conversion element housing section of the first optical module holder section. Relative positions of the first optical module holder section and the second optical module holder section are adjusted.