A linear friction-joining device comprising: a pressing device including a jig on which a second member is loaded and a cylinder device which moves the jig for pressing the second member onto a first member in a pressing direction; a vibrator for relatively vibrating the first member and the second member; a position sensor configured to measure a displacement amount of the second member in the pressing direction; a load sensor configured to measure a pressing load of the second member pressed onto the first member; a controller (40, 41) configured to bring the second member into contact with the first member by a position control, which depends on a measurement result of the position sensor, to change the position control to a load control, which depends on a measurement result of the load sensor, and to increase the pressing load toward a joining load; and a joining load reaching time adjuster configured to adjust a length of a joining load reaching time (t) which is between the time when the position control is changed to the load control and the time when the pressing load reaches the joining load, characterized in that: the jig is provided with a second load sensor for measuring a weight of the second member loaded onto the jig, the cylinder device is provided with a third load sensor for measuring a weight of the jig, the joining load reaching time adjuster is the controller (40, 41) which is configured to adjust the length of the joining load reaching time (t) according to a magnitude of an inertial force in the pressing direction acting on the second member during the position control, and the magnitude of the inertial force in the pressing direction acting on the second member depending on the weights of the second member and the jig and on a deceleration acceleration of the second member from a constant speed movement to a zero speed during the position control. a pressing device including a jig on which a second member is loaded and a cylinder device which moves the jig for pressing the second member onto a first member in a pressing direction; a vibrator for relatively vibrating the first member and the second member; a position sensor configured to measure a displacement amount of the second member in the pressing direction; a load sensor configured to measure a pressing load of the second member pressed onto the first member; a controller (40, 41) configured to bring the second member into contact with the first member by a position control, which depends on a measurement result of the position sensor, to change the position control to a load control, which depends on a measurement result of the load sensor, and to increase the pressing load toward a joining load; and a joining load reaching time adjuster configured to adjust a length of a joining load reaching time (t) which is between the time when the position control is changed to the load control and the time when the pressing load reaches the joining load, characterized in that: the jig is provided with a second load sensor for measuring a weight of the second member loaded onto the jig, the cylinder device is provided with a third load sensor for measuring a weight of the jig, the joining load reaching time adjuster is the controller (40, 41) which is configured to adjust the length of the joining load reaching time (t) according to a magnitude of an inertial force in the pressing direction acting on the second member during the position control, and the magnitude of the inertial force in the pressing direction acting on the second member depending on the weights of the second member and the jig and on a deceleration acceleration of the second member from a constant speed movement to a zero speed during the position control. the jig is provided with a second load sensor for measuring a weight of the second member loaded onto the jig, the cylinder device is provided with a third load sensor for measuring a weight of the jig, the joining load reaching time adjuster is the controller (40, 41) which is configured to adjust the length of the joining load reaching time (t) according to a magnitude of an inertial force in the pressing direction acting on the second member during the position control, and the magnitude of the inertial force in the pressing direction acting on the second member depending on the weights of the second member and the jig and on a deceleration acceleration of the second member from a constant speed movement to a zero speed during the position control.