A connector assembly comprising: a first connector including a first insulator and a first contact held by the first insulator; a second connector (21, 41) including a second insulator and a second contact held by the second insulator, the second connector being fitted to the first connector along a fitting direction; a contact spring member (31F, 51A) attached to the second contact and including a pressing portion (31K, 51B) configured to press the first contact against the second contact to bring the first contact and the second contact into contact with each other; a lever member held by the second insulator and being rotatable about a rotational axis between a first rotational position and a second rotational position; a fitting cam mechanism (13D, 22D) relatively moving the first insulator and the second insulator along the fitting direction in conjunction with rotation of the lever member, characterized in that it further comprises a rotational shaft member (25, 45) held by the second insulator to rotate about the rotational axis along with rotation of the lever member and including a cam surface (25H, F12) configured to elastically deform the contact spring member; and when the lever member is placed in the second rotational position, the cam surface of the rotational shaft member makes contact with and elastically deforms the contact spring member, whereby a first contact insertion portion that allows the first contact to be inserted thereinto along the fitting direction is formed between the pressing portion and the second contact, and in a state where the first connector and the second connector are fitted together and the first contact is inserted in the first contact insertion portion, when the lever member is rotated from the second rotational position to the first rotational position, fitting between the first connector and the second connector is locked by the fitting cam mechanism, and the cam surface of the rotational shaft member is moved away from the contact spring member, so that the first contact and the second contact are pressed against each other by the pressing portion to make contact with each other. a first connector including a first insulator and a first contact held by the first insulator; a second connector (21, 41) including a second insulator and a second contact held by the second insulator, the second connector being fitted to the first connector along a fitting direction; a contact spring member (31F, 51A) attached to the second contact and including a pressing portion (31K, 51B) configured to press the first contact against the second contact to bring the first contact and the second contact into contact with each other; a lever member held by the second insulator and being rotatable about a rotational axis between a first rotational position and a second rotational position; a fitting cam mechanism (13D, 22D) relatively moving the first insulator and the second insulator along the fitting direction in conjunction with rotation of the lever member, characterized in that it further comprises a rotational shaft member (25, 45) held by the second insulator to rotate about the rotational axis along with rotation of the lever member and including a cam surface (25H, F12) configured to elastically deform the contact spring member; and when the lever member is placed in the second rotational position, the cam surface of the rotational shaft member makes contact with and elastically deforms the contact spring member, whereby a first contact insertion portion that allows the first contact to be inserted thereinto along the fitting direction is formed between the pressing portion and the second contact, and in a state where the first connector and the second connector are fitted together and the first contact is inserted in the first contact insertion portion, when the lever member is rotated from the second rotational position to the first rotational position, fitting between the first connector and the second connector is locked by the fitting cam mechanism, and the cam surface of the rotational shaft member is moved away from the contact spring member, so that the first contact and the second contact are pressed against each other by the pressing portion to make contact with each other.