The image pickup optical system comprises: an aperture is placed on the most object side, the image pickup optical system comprises, in order from the object side: a first lens having a positive refractive power; a second lens having a negative refractive power; a third lens having a positive refractive power; a fourth lens having a positive refractive power; and a fifth lens having a negative refractive power, and the following conditional expression is satisfied: −1.49