Yes and no. When the beta particle, lets assume it is a negative beta particle, is emitted by a nucleus, a neutron (which is neutral) is converted into a proton (positive) and an electron (negative) inside the nucleus, thus maintaining the conservation of charges. It is this electron, which we call the beta particle, that is emitted.
Now the increase in the number of protons changes the Atomic Number of element, thus converting it into a conpletely different element with new properties. This new atom is positively charged, provided that the original atom was neutral, since now the number of protons has increased by 1, while the number of electrons around the nucleus stays the same.
If however, a positive beta particle (i.e. a positron) is emitted, than a neutral atom of an element will not only be converted into another element, but will also become negatively charged.