An encased syringe in which a prefilled syringe is accommodated in a case, wherein the prefilled syringe includes a cylindrical syringe body filled with a foamable material; a nozzle provided at an end of the syringe body; and a plunger pressed into the syringe body on one end side, the case includes a syringe accommodating part that includes a body accommodating part formed to be depressed along a shape of the syringe body to accommodate the syringe body; a nozzle accommodating part formed to be depressed along a shape of the nozzle to accommodate the nozzle, the nozzle accommodating part being different in depth from the body accommodating part; and a plunger accommodating part formed to be depressed along a shape of the plunger to accommodate the plunger, wherein the length (Lc) of the plunger accommodating part is smaller than the length (Lp) of the plunger in an axial direction of the prefilled syringe, characterized in that the syringe body is locked by a step between the nozzle accommodating part and the body accommodating part that are different in depth, wherein said difference in depth defines said step so that a displacement of the prefilled syringe accommodated in the syringe accommodating part toward a side of the nozzle in an axial direction of the prefilled syringe accommodated in the syringe accommodating part is restricted. the prefilled syringe includes a cylindrical syringe body filled with a foamable material; a nozzle provided at an end of the syringe body; and a plunger pressed into the syringe body on one end side, a cylindrical syringe body filled with a foamable material; a nozzle provided at an end of the syringe body; and a plunger pressed into the syringe body on one end side, the case includes a syringe accommodating part that includes a body accommodating part formed to be depressed along a shape of the syringe body to accommodate the syringe body; a nozzle accommodating part formed to be depressed along a shape of the nozzle to accommodate the nozzle, the nozzle accommodating part being different in depth from the body accommodating part; and a plunger accommodating part formed to be depressed along a shape of the plunger to accommodate the plunger, wherein the length (Lc) of the plunger accommodating part is smaller than the length (Lp) of the plunger in an axial direction of the prefilled syringe, a body accommodating part formed to be depressed along a shape of the syringe body to accommodate the syringe body; a nozzle accommodating part formed to be depressed along a shape of the nozzle to accommodate the nozzle, the nozzle accommodating part being different in depth from the body accommodating part; and a plunger accommodating part formed to be depressed along a shape of the plunger to accommodate the plunger, characterized in that the syringe body is locked by a step between the nozzle accommodating part and the body accommodating part that are different in depth, wherein said difference in depth defines said step so that a displacement of the prefilled syringe accommodated in the syringe accommodating part toward a side of the nozzle in an axial direction of the prefilled syringe accommodated in the syringe accommodating part is restricted.