證(zheng)券(quan)公(gong)(gong)(gong)司(si)(si)是指依(yi)照《公(gong)(gong)(gong)司(si)(si)法(fa)》和(he)《證(zheng)券(quan)法(fa)》的規定設立的并經國務(wu)院證(zheng)券(quan)監督管(guan)理機構審查(cha)批準而成立的專門經營證(zheng)券(quan)業務(wu)，具有獨立法(fa)人地(di)位的有限(xian)責任公(gong)(gong)(gong)司(si)(si)或者股份有限(xian)公(gong)(gong)(gong)司(si)(si)。

證券公司（Securiti，es Company）是專(zhuan)門從事有(you)價證券(quan)(quan)(quan)(quan)(quan)買賣的法人企業(ye)。分(fen)為證券(quan)(quan)(quan)(quan)(quan)經營公(gong)(gong)司(si)和(he)證券(quan)(quan)(quan)(quan)(quan)登記公(gong)(gong)司(si)。狹義(yi)的證券(quan)(quan)(quan)(quan)(quan)公(gong)(gong)司(si)是指(zhi)證券(quan)(quan)(quan)(quan)(quan)經營公(gong)(gong)司(si)，是經主(zhu)管機(ji)關(guan)批準并到有(you)關(guan)工商行政管理(li)局(ju)領(ling)取(qu)營業(ye)執照后專(zhuan)門經營證券(quan)(quan)(quan)(quan)(quan)業(ye)務的機(ji)構。它具(ju)有(you)證券(quan)(quan)(quan)(quan)(quan)交易所(suo)的會員資格，可以承銷發行、自(zi)營買賣或自(zi)營兼代(dai)理(li)買賣證券(quan)(quan)(quan)(quan)(quan)。普(pu)通(tong)投(tou)資人的證券(quan)(quan)(quan)(quan)(quan)投(tou)資都要通(tong)過(guo)證券(quan)(quan)(quan)(quan)(quan)商來進行。

在(zai)(zai)不同(tong)的國(guo)家，證(zheng)(zheng)券公(gong)司(si)有(you)著不同(tong)的稱謂(wei)。在(zai)(zai)美國(guo)，證(zheng)(zheng)券公(gong)司(si)被稱作投資銀行（Investment Bank）或者證券(quan)經紀商(shang)（Broker-Dealer）；在英(ying)國，證(zheng)券公(gong)司被稱作商人銀行（Merchant Bank）；在歐(ou)洲大陸（以(yi)德(de)國為代表），由于一直沿用混業經營制度，投(tou)資銀(yin)行僅是全(quan)能銀(yin)行（Universal Bank）的一個(ge)部(bu)門；在東亞（以日(ri)本為代表），則被稱(cheng)為證券公司（Securities Company）。