The present invention aims to provide a small-sized high-efficiency high pressure discharge lamp that exhibits favorable light intensity distribution properties and is less likely to cause breakage of an arc tube. The present invention is a high pressure discharge lamp 101 comprising: an arc tube 110 that includes; a light-emitting part 111 having a substantially spherical shape and having mercury enclosed therein; and a pair of sealing parts 112 extending from opposite sides of the light-emitting part 111; and a pair of electrodes 130 that are arranged in the arc tube 110 such that an end of each electrode is sealed by a respective sealing part and the other ends of the electrodes oppose each other in the light-emitting part. The enclosed mercury has a density of 0.2 to 0.4 [mg/mm3] inclusive. A distance W from a contact point S to a center O is 3.0 to 5.0 [mm] inclusive. A distance CO from a contact point TO to the center O is 1.5 to 3.0 [mm] inclusive. The distance CO and a distance CM satisfy a relation CM/CO≧0.8, and a minimum thickness X [mm] and a maximum outer diameter D [mm] satisfy a relation X/D≧0.2.