To provide a pedestal in which a groove part used to relax a stress can be formed easily.

First, a silicon wafer 1 which is composed of a low-concentration layer 1a, a high-concentration layer 1b and a low-concentration layer 1c is prepared. Silicon nitride films 2 are formed on both faces of the silicon wafer 1. The silicon nitride films 2 are patterned, and opening parts 2a are formed. Then, while the silicon nitride films 2 in which the opening parts 2a are formed are used as masks, an anisotropic etching operation which reaches the high-concentration layer 1b is performed, and cutout parts 3 which reaches the high-concentration layer 1b are formed. A fluoronitric acid solution is introduced from the cutout parts 3. Pressure introduction holes 4 and groove parts 5 are formed by an isotropic etching operation. The silicon nitride films 2 on both faces of the silicon wafer 1 are etched so as to be removed. Thereby, pedestals are formed. Then, a semiconductor sensor chip 6 is bonded to the low-concentration layer 1c in the silicon wafer 1. The semiconductor sensor chip 6 and the pedstals are diced so as to pass the groove parts 5 other than parts in which the pressure introduction holes 4 are formed. This assembly is divided into chips. A semiconductor pressure sensor which has the groove parts on the outer circumferential face of every pedestal is manufactured.