Problem to be solved: to provide an imaging optical system and an imaging apparatus realizing wide angle of view and miniaturization, i.e., miniaturization and short optical length while maintaining excellent imaging performance by correcting aberrations with high accuracy.Solution: the first lens G1 having negative refractive power, the second lens G2 having positive refractive power, the third lens G3 having positive refractive power, the fourth lens G4 and the fifth lens G5, and the fourth lens G4 and the fifth lens G5 are not joined to each other, and are not joined to each other An imaging optical system characterized by satisfying a predetermined conditional expression.Diagram【課題】収差を高精度に補正して優れた結像性能を維持しつつ、広画角化、及び小型化すなわち小口径化と短い光学全長とを実現した結像光学系及び撮像装置を提供すること。【解決手段】物体側から順に、負の屈折力を有する第１レンズＧ１と、正の屈折力を有する第２レンズＧ２と、正の屈折力を有する第３レンズＧ３と、第４レンズＧ４と、第５レンズＧ５とを有し、第４レンズＧ４と第５レンズＧ５とは接合されておらず、所定の条件式を満足することを特徴とする結像光学系。【選択図】図１
