We present a catalog of star clusters with V _ { F 555 W } < 23 mag detected in the interacting spiral galaxy M51 system based on the mosaic images taken with HST ACS by the Hubble Heritage Team .
We have selected about 3,600 clusters based on their morphological information through the visual inspection .
The final star cluster catalog includes 2,224 clusters that are relatively well isolated and have a circular shape .
The star clusters in M51 are mostly distributed around the spiral arms of NGC 5194 .
The color-magnitude diagrams show that most of the star clusters in M51 are bluer than ( B _ { F 435 W } - V _ { F 555 W } ) = 0.5 and ( V _ { F 555 W } - I _ { F 814 W } ) = 0.8 .
There are also some red star clusters with ( B _ { F 435 W } - V _ { F 555 W } ) > 0.7 , uniformly distributed over the M51 field .
Some of these red clusters are suspected to be a part of the halo or old disk population based on their old ages ( t \geq 10 ^ { 9 } yrs ) and their spatial distribution .
The luminosity function of the star clusters is fit well by a single power law with \alpha = -2.59 \pm 0.03 for the range -10.0 < M _ { V } < -8.0 mag .
We find that the size distribution of the star clusters can be fit with three Gaussian components with peaks at effective radii of 2.27 , 4.80 and 7.51 pc .
Some large star clusters with red color are faint fuzzy clusters , and they are distributed not only around NGC 5195 but also around NGC 5194 .
These faint fuzzies are found to display an elongated spatial distribution , while the normal compact red clusters show a relatively uniform distribution around NGC 5194 .