1. An antithrombogenic medical material comprising:
a nickel-titanium alloy;
a polyelectrolyte bound to a surface of the nickel-titanium alloy; and
an antithrombogenic compound bound to the polyelectrolyte, the antithrombogenic compound having a charge opposite to the charge of the polyelectrolyte; wherein
the following Formula 1 is satisfied according to measurement using X-ray photoelectron spectroscopy (XPS), and
the following Formula 2 is satisfied according to measurement using Auger electron spectroscopy (AES).
1 Iraticb xps > 2 ... Formula 1 [wherein in Formula 1, Tiraiti05 XPS represents the abundance ratio (atomic percentage) of titanium element to the abundance of total elements as measured by XPS on a surface of the medical material]
^ratio, AES > 7 ... Formula 2 [wherein in Formula 2, Crati0, AES represents the abundance ratio (atomic percentage) of carbon element to the abundance of total elements on a surface of the medical material subjected to argon ion etching to 20 nm in terms of Si02]
2. The antithrombogenic medical material according to claim 1, wherein the polyelectrolyte is a cationic polymer containing a monomer selected from the group consisting of alkyleneimines, vinylamines, allylamines, lysine, arginine, histidine, protamine, glucosamine, and diallyldimethylammonium chloride.
3. The antithrombogenic medical material according to claim 1, wherein the polyelectrolyte is an anionic polymer containing a monomer selected from the group

consisting of acrylic acid, a-hydroxyacrylic acid, vinylacetic acid, vinylsulfonic acid, allylsulfonic acid, vinylphosphonic acid, allylphosphonic acid, aspartic acid, and glutamic acid.
4. The antithrombogenic medical material according to any one of claims 1 to 3, wherein the antithrombogenic compound is selected from the group consisting of heparin, heparin derivatives, dextran sulfate, polyvinyl sulfonate, polystyrene sulfonate, argatroban, beraprost sodium, ozagrel, and cangrelor.
5. The antithrombogenic medical material according to any one of claims 1 to 4, wherein
the following Formula 3 is satisfied according to measurement using Auger electron spectroscopy (AES), and
the argon ion etching depth is not less than 20 nm in terms of SiC^.
Oratio / Max (Oratio) = 0.5 ... Formula 3 [wherein in Formula 3, Oratio represents the abundance ratio (atomic percentage) of oxygen element to the abundance of total elements on a surface of the medical material subjected to argon ion etching, and Max (Oratio) represents the maximum
Value Of Oratio]