A thruster designed to produce thrust by introducing a propellant to a catalyst layer from a propellant valve via a propellant introduction member and spurting out a gas resulting from decomposition of the propellant occurring on the catalyst layer, wherein the thruster comprises a chamber of an Ni alloy for holding the catalyst layer inside, the propellant introduction member is made of an Ni alloy and connects the propellant valve and the chamber, and a propellant valve flange of a Ti alloy with a plurality of columns of a Ti alloy is arranged between the chamber and the propellant valve to support the chamber by the columns.