A syringe has a syringe main body, a syringe unit, and a piston, wherein a plunger has a rod portion which extends toward the piston from an end surface disposed on a proximal end side in an attached state in which the syringe unit is attached to the syringe main body. An opening is provided on a forward end side of the piston so that the rod portion of the plunger can be inserted thereinto, and an accommodating hole is provided and formed so that an end portion of the rod portion disposed on the proximal end side is accommodated without making contact with the piston. An end surface of the piston disposed on the forward end side is brought in contact with the end surface of the plunger disposed on the proximal end side so that the plunger is slidable toward a discharge port in a state in which the rod portion is accommodated in the accommodating hole in the attached state, and a position of the plunger in the charging chamber is determined at a predetermined position at which an amount of an injection objective substance in the charging chamber is a predetermined amount on the basis of a position of the piston arranged in the through-hole. Accordingly, the syringe is easily handled and the injection objective substance such as an injection solution or the like can be correctly charged.
