Multi-channel optical device and optical module

The invention provides a multichannel optical device and an optical module.The multichannel optical device comprises a non-airtight sealing box, an airtight sealing box and a wavelength division multiplexer, the non-airtight sealing box comprises a base and a first side wall, and the first side wall is provided with a first through hole; the airtight sealing box is fixed to the portion, at the end opposite to the first side wall, of the base and penetrates through and is connected to the second side wall, a transparent window is arranged on one side wall of the airtight sealing box, and the end, provided with the transparent window, of the airtight sealing box is inserted into the non-airtight sealing box; the wavelength division multiplexer is arranged on the base in the non-airtight sealing box, the wavelength division multiplexer comprises more than two light inlet and outlet surfaces, one light inlet and outlet surface is arranged opposite to the transparent window, and the other light inlet and outlet su