PROBLEM TO BE SOLVED: To provide an impression tray for a lower jaw, made of a plastic, and capable of highly accurately taking an impression by preventing a cured impression material from floating upward from the tray or being peeled off the tray.SOLUTION: An impression tray for a lower jaw made of a plastic includes: an outer wall 2 and an inner wall 3 respectively on the outer side and the inner side of a bottom 1 forming a U-shaped plane with an approximately uniform width. The impression tray also includes: a rim 4 of a specific height provided on the bottom 1 side along the upper ends of the outer wall 2 and the inner wall 3 slot-shaped through-holes 5 of a specific width reaching the bottom 1 from just below the rim 4 at right angles to the rim 4 provided in such a way that an interval between adjacent slot-shaped through-holes 5 is a specific number of times of the width of each through-hole 5 round through-holes 6 of a specific diameter provided at the center of the interval between the adjacent slot-shaped through-holes 5 on the bottom 1 and slot-shaped bottom through-holes 7 of a specific width and a specific length provided on lines connecting bottom side ends of the slot-shaped through-holes located on ends of the U shape, the most end sides of the U shape, or further on the end sides from the lines.COPYRIGHT: (C)2013,JPO&INPIT【課題】硬化後の印象材のトレーからの浮き上がりや剥離を防止して精度の高い印象採得を行うことができるプラスチック製の下顎用の印象用トレーを提供する。【解決手段】U字状で略同一幅の平面を成す底部1の外側と内側外壁2と内壁3とを有するプラスチック製の下顎用の印象用トレーであって、外壁2と内壁3との各上端に沿って底部1側に特定高さのリム4を、リム4に対して直角にリム4の直下から底部1に達する特定幅の長穴状の貫通穴5を隣接する間隙が貫通穴の幅の特定倍に、且つ底部1には前記長穴状の貫通穴5の隣接する間隔の中央に特定直径の円形貫通穴6を、U字状の端部であってU字状の最も端部側に位置する前記各長穴状の貫通穴5の底部側端部を結ぶ線上又はこの線より端部側には特定幅で特定長さの長穴状の底部貫通穴7を、それぞれ設ける。【選択図】図1