A syringe transmits energy for injection satisfactorily to an injection objective substance while preventing influences of combustion products produced by the combustion of powder on the injection objective substance. A first piston part has a specific end face that receives ejection energy. A sealing member confines the combustion products in a first space separated by the sealing member. The sealing member has a fixed end portion and a contact portion that is in contact with the specific end face. In a state before the combustion of powder in an igniter, the contact portion is located at an initial position. With the combustion of powder in the igniter, the contact portion shifts to an ejection position with the sliding motion of the first piston part while being in contact with the specific end portion.