A piezoelectric power generation device comprising a plurality of power generation elements each of which includes: a support body configured by a plate-like planar portion having one main surface and the other main surface and a projecting portion projecting from a center portion of the other main surface of the planar portion, and a piezoelectric body provided on the one main surface of the planar portion, and is arranged such that the piezoelectric body overlaps with the projecting portion when the support body is seen in plan view along a direction perpendicular to the one main surface of the planar portion, wherein the plurality of power generation elements overlap with one another in the direction perpendicular to the one main surface , and the support body in at least one power generation element of a pair of adjacent power generation elements includes a plurality of leg portions projecting from a peripheral edge portion of at least a main surface of the one main surface and the other main surface of the planar portion at the other power generation element side, the peripheral edge portion being located in an outer side portion relative to the center portion, characterized in that the plurality of power generation elements overlap with each other with the leg portions interposed between the power generation elements such that the other main surface of the support body of one power generation element of the pair of adjacent power generation elements and the one main surface of the support body of the other power generation element oppose each other, wherein the support body of at least one power generation element among the plurality of power generation elements is formed such that a thickness of a center portion of the projecting portion is larger than a thickness of a peripheral edge portion located in an outer side portion relative to the center portion. a support body configured by a plate-like planar portion having one main surface and the other main surface and a projecting portion projecting from a center portion of the other main surface of the planar portion, and a piezoelectric body provided on the one main surface of the planar portion, and is arranged such that the piezoelectric body overlaps with the projecting portion when the support body is seen in plan view along a direction perpendicular to the one main surface of the planar portion, wherein the plurality of power generation elements overlap with one another in the direction perpendicular to the one main surface , and the support body in at least one power generation element of a pair of adjacent power generation elements includes a plurality of leg portions projecting from a peripheral edge portion of at least a main surface of the one main surface and the other main surface of the planar portion at the other power generation element side, the peripheral edge portion being located in an outer side portion relative to the center portion, characterized in that the plurality of power generation elements overlap with each other with the leg portions interposed between the power generation elements such that the other main surface of the support body of one power generation element of the pair of adjacent power generation elements and the one main surface of the support body of the other power generation element oppose each other, wherein the support body of at least one power generation element among the plurality of power generation elements is formed such that a thickness of a center portion of the projecting portion is larger than a thickness of a peripheral edge portion located in an outer side portion relative to the center portion. <EOS>