  We present the Spitzer MIPS 24 micron source counts in the Extragalactic
First Look Survey main, verification and ELAIS-N1 fields. Spitzer's increased
sensitivity and efficiency in large areal coverage over previous infrared
telescopes, coupled with the enhanced sensitivity of the 24 micron band to
sources at intermediate redshift, dramatically improve the quality and
statistics of number counts in the mid-infrared. The First Look Survey
observations cover areas of, respectively, 4.4, 0.26 and 0.015 sq.deg. and
reach 3-sigma depths of 0.11, 0.08 and 0.03 mJy. The extragalactic counts
derived for each survey agree remarkably well. The counts can be fitted by a
super-Euclidean power law of index alpha=-2.9 from 0.2 to 0.9 mJy, with a
flattening of the counts at fluxes fainter than 0.2 mJy. Comparison with
infrared galaxy evolution models reveals a peak's displacement in the 24 micron
counts. This is probably due to the detection of a new population of galaxies
with redshift between 1 and 2, previously unseen in the 15 micron deep counts.
