Air cleaner apparatus and straddle-type vehicle equipped with the apparatus

An air cleaner apparatus (102) has an air cleaner case (105), a main filter element (170) dividing an interior of the air cleaner case (105) into a first chamber (115) and a second chamber (145), an intake passage (130) for sucking air outside the air cleaner case (105) into the first chamber (115), a discharge passage (148) for discharging the air within the second chamber (145) out of the air cleaner case (105), and a pre-filter element (138) including a wet-type element disposed in the first chamber (115). The intake passage (130) has an air outlet port (132) for blowing off air into the first chamber (115). The pre-filter element (138) is disposed spaced apart from the air outlet port (132) so as to be positioned on the axis line of the air outlet port (132).