A method of manufacturing a mechanical quantity sensor, comprising: forming a semiconductor substrate by sequentially stacking a first layer formed of a first semiconductor material, a second layer formed of an insulating material, and a third layer formed of a second semiconductor material; forming a first structure in the first layer having a fixed portion with an opening, a (displaceable portion arranged in the opening and (displaceable relative to the fixed portion, and a connection portion connecting the fixed portion and the (displaceable portion, by etching the first layer of the semiconductor substrate arranging and stacking a first base formed of an insulating material on the first structure by joining the first base to the fixed portion; forming a second structure in the third layer having a weight portion joined to the displaceable portion, a projection arranged on a face of the weight portion on a side opposite to a face joined to the displaceable portion or on a face of an area of the third layer where the weight portion is to be formed on a side opposite to a face joined to the displaceable portion, and a pedestal arranged surrounding the weight portion and joined to the fixed portion, by etching the third layer; and arranging and stacking a second base on the second structure by anodically bonding the second base to the pedestal, the second base formed of an insulating material and having a first driving electrode arranged on a face facing the weight portion, formed of a conductive material, for applying vibration in a stacking direction to the displaceable portion, and a first detection electrode (154b to 154e) arranged on a face facing the weight portion, formed of a conductive material, for detecting a displacement of the displaceable portion, wherein the projection is arranged in an area corresponding to an area where the first driving electrode and the first detection electrode (154b to 154e) are not arranged, and has a thickness larger than thicknesses of the first driving electrode and the first detection electrode (154b to 154e). forming a semiconductor substrate by sequentially stacking a first layer formed of a first semiconductor material, a second layer formed of an insulating material, and a third layer formed of a second semiconductor material; forming a first structure in the first layer having a fixed portion with an opening, a (displaceable portion arranged in the opening and (displaceable relative to the fixed portion, and a connection portion connecting the fixed portion and the (displaceable portion, by etching the first layer of the semiconductor substrate arranging and stacking a first base formed of an insulating material on the first structure by joining the first base to the fixed portion; forming a second structure in the third layer having a weight portion joined to the displaceable portion, a projection arranged on a face of the weight portion on a side opposite to a face joined to the displaceable portion or on a face of an area of the third layer where the weight portion is to be formed on a side opposite to a face joined to the displaceable portion, and a pedestal arranged surrounding the weight portion and joined to the fixed portion, by etching the third layer; and arranging and stacking a second base on the second structure by anodically bonding the second base to the pedestal, the second base formed of an insulating material and having a first driving electrode arranged on a face facing the weight portion, formed of a conductive material, for applying vibration in a stacking direction to the displaceable portion, and a first detection electrode (154b to 154e) arranged on a face facing the weight portion, formed of a conductive material, for detecting a displacement of the displaceable portion, wherein the projection is arranged in an area corresponding to an area where the first driving electrode and the first detection electrode (154b to 154e) are not arranged, and has a thickness larger than thicknesses of the first driving electrode and the first detection electrode (154b to 154e).