A device includes a first substrate (903), a second substrate (100) on the first substrate (903), and a light emitting device (11) including a light source (300) on the second substrate (100) and that emits light toward an object. The light emitting device includes a driver (200) disposed in the second substrate (100) and that drives the light source (300). A portion of the driver (200) overlaps a first portion of the light source (300) in a plan view. The device includes an imaging device (12) on the first substrate adjacent to the light emitting device (11) and that senses light reflected from the object. The light-emitting device (11) reduces the wiring inductance by electrically connecting the light source (300) and the driver (200) via the connecting via (101). Further, the second substrate (100) includes a thermal via (102) for heat radiation. Considering that a certain number of thermal vias (102) are arranged immediately below the light source (300), the amount of overlap is desirably 50% or less. An upper surface surrounded by side wall (600) is covered by a diffuser plate (700). A light-receiving element (910) may be directly mounted as a bare chip on the substrate (903) by using an epoxy or silicone die attach material. The light source (300) preferably includes a semiconductor laser.