Provided is a contrast medium (1) comprising at least one molecular probe (3 to 5) and at least one optical probe (6) on a surface of a substrate (2) having an ultrasound imaging function. More specifically, a contrast medium (1) having sensitivity to not only ultrasound but also light excellent in real-time imaging and resolution and having a size sufficient to travel into tissues through blood vessel can be provided by labelling an ultrasound imageable substrate (2) with a molecular probe (3 to 5) and an optical probe (6).
