A light receiving and emitting device includes: a light emitting unit and a light receiving unit which are provided on a same substrate, wherein the light emitting unit includes an active layer sandwiched between a first clad layer and a second clad layer, a first electrode electrically connected to the first clad layer, and a second electrode electrically connected to the second clad layer, the light receiving unit includes a light-absorbing layer, at least part of the active layer forms a gain region on a current path between the first electrode and the second electrode, the gain region is provided from a first side face of the active layer to a second side face parallel to the first side face so as to be inclined with respect to a perpendicular of the first side face as seen in a planar view, a light generated in the gain region is divided, at least one of an edge face on the first side face and an edge face on the second side face, the edge faces of the gain region, into a light emitted to an outside and a reflected light, and the reflected light is received by the light receiving unit.