A cartridge fitting portion of a cylindrical syringe made of a resin includes an end surface opening portion, a continuous opening portion continuous with the end surface opening portion, opened in a radial direction, and extending in an extending direction, and a recess portion configured to communicate with the end surface opening portion, the continuous opening portion, and an internal passage in a cylindrical body. The recess portion includes a flange fitting recess to be fitted with a flange portion of a cartridge, and a cylindrical portion fitting recess that communicates with the flange fitting recess and is fitted with a part of the cylindrical portion. A wall portion surrounding the cylindrical portion fitting recess of the cartridge fitting portion is configured to warp into snap engagement with the part of the cylindrical portion when the part of the cylindrical portion is inserted from the continuous opening portion.