In the present invention, a fluid handling device has: a first substrate made of resin whereon a channel is formed in a first surface; a first film made of resin and joined to the first surface of the first substrate; a second film made of resin a first surface of which is joined to a second surface of the first substrate; and a second substrate made of resin and joined to a second surface of the second film. A recessed part overlapping the channel in a plane view is formed on the surface of the second substrate joined to the second film. The glass transition temperature Tg1s of the first substrate, the glass transition temperature Tg1f of the first film, the glass transition temperature Tg2s of the second substrate, and the glass transition temperature Tg2f of the second film satisfy Tg1s, Tg2s>Tg1f, Tg2f.