A light distribution of light from a light-emitting device (10) has a higher luminous intensity in a first direction (D1) compared to a reference direction (R), the first direction (D1) being different from the reference direction (R). The reference direction (R) is a center direction of the light distribution, for example, a direction along the thickness direction of a substrate (100), a direction along the width direction of each layer (for example, an EML (126)) of a resonator (150), or a normal direction of a second surface (104) of the substrate (100). In addition, the light distribution has a higher luminous intensity in a second direction (D2) compared to the reference direction (R), the second direction (D2) being on an opposite side of the first direction (D1) with respect to the reference direction (R).