A handheld hemoglobin detecting device has a housing assembly including a holding base, a tubular housing and a liquid holder, a control module disposed on the housing assembly, and a lighting assembly mounted in the tubular housing and including a light emitting module, a light concentrator, and a light guide. At least one light beam emitted from the light emitting module passes through and is concentrated by the light concentrator to shine on the liquid holder, is reflected by a light reflector that is disposed in the liquid holder, enters the light guide, and is transmitted to a light sensor. The handheld hemoglobin detecting device has a simplified structure and is easy to assemble, and thus is light and has low manufacturing cost. Moreover, a lower accuracy in assembling the lighting assembly can be tolerated.
