An optical device comprises optical fibers and a holder. The holder includes one end portion, an other end portion, and a supporting portion extending in a direction of a first axis from the one end portion to the other end portion. The one end portion includes a first end face extending along a first reference plane intersecting with the first axis from a side of the holder to cladding regions of the optical fibers; a second end face extending along a second reference plane from the one end portion to the other end portion; and a third end face extending along a third reference plane inclined at an angle of less than 90 degrees and more than zero degrees relative to the first axis. The cladding regions of the optical fibers are disposed at the second end face. The optical fibers have respective tips disposed at the third end face.